Zimbra Modern Desktop

Zimbra Desktop is a desktop email client that gives you online and offline access to your Zimbra email. More than just another choice in the email client landscape, Zimbra Desktop blurs the line bet

Zimbra Desktop uses the same technology as Zimbra's Web Application, has intuitive navigation, supports customizations, and is secure.

Zimbra Desktop app is supported on Windows 10 or newer versions and Mac 10.13 or newer versions.

Getting Started

Setting up Zimbra Desktop app

Setting up the Zimbra Desktop app is easy. When the Desktop app is opened for the first time, users will have to provide the Zimbra Server URL for the Desktop App to connect to the Zimbra server.

Users need to perform this step only once when accessing the Zimbra Desktop app for the first time.

  1. Open the Zimbra Desktop app. Specify the organization’s Zimbra Server URL in the text box. For Bamboozle Business email the link is https://bbzmail.me

  2. Click Continue.

  3. Enter your username in the Email field.

  4. Enter your password in the Password field.

  5. Click Sign in to login.

Upon successful authentication, user will be logged into his Inbox.

First login

When a user logs in for the first time in the Zimbra Desktop app, by default last 30 days' mail data will be downloaded to their local storage. Users can go to cog iconSettingsOffline and choose a date to download older emails to the local storage.

Offline Functionality

Zimbra intends to provide a consistent user experience across all types of devices and hence the desktop application has been designed to support almost all the functionality available in the Zimbra Web App.

In the following documentation:

  • The term Online is used to refer to a scenario when the Zimbra Desktop app is connected to the Internet.

  • The term Offline is used to refer to a scenario when the Zimbra Desktop app is not connected to the Internet.

When Zimbra Desktop app is online

All Zimbra Web App functionalities are available when a user is online.

When Zimbra Desktop app is offline

Most of the core mail related functionalities are available to the user even when the desktop application is offline.

The following features are available when the desktop application is offline:

  • View emails.

  • View and download attachments.

  • Reply, Reply All, Forward an email.

  • Compose a new mail.

  • Send a new mail.

  • Mark email as read.

  • Star / Unstar an email.

  • Mark email as spam.

  • Archive an email.

  • Delete an email.

  • Move an email.

  • Create sub-folders under Local Folders.

  • Message View.

  • All formatting options in Mail Composer.

  • Search limited to keywords: from, to, cc, subject, in, has, date.

  • Limited access to events in Calendar vertical.

  • Limited access to contacts in Contacts vertical.

While users can perform all of these actions while offline, they will get executed only when the user goes online. For example, a user may send a mail while offline, however the mail will leave the user’s Outbox only when the user goes online.

The following features are not available when the desktop application is offline:

  • Following options in the Folder Context Menu (i.e. on folder right-click).

    • Import.

    • Share.

    • Create subfolder.

    • Export.

    • Empty folder.

  • Following options in the Trash Folder Context Menu (i.e. on folder right-click).

    • Mark emails as read.

    • Empty Trash.

    • Export.

    • Recover discarded mail.

  • Following options in the Mail Context Menu (i.e. on email right-click)

    • Tag.

    • Block.

    • Print.

    • New Event.

    • New Filter.

    • Mark as Spam.

    • Show Original.

    • Add Sender to Contacts.

  • Schedule Send.

  • Create, Edit, Delete tag.

  • Access to all contacts.

  • Access to all calendar items.

  • Accept, Tentative, Decline, Propose New Time options on a meeting invite.

  • Conversation View.

  • Mail Preview Pane settings.

  • Advanced Search.

  • Contact Chooser from To field in Composer.

  • cog iconSettings.

  • cog iconLanguage.

  • cog iconHelp.

  • Video, Chat and Cloud Storage verticals.

Access to locally stored messages

When logging in for the first time, the user will see the login screen. The user needs to provide valid credentials to log into his account. Upon successful login, mails will be downloaded to the user’s local storage. Users will always have access to these downloaded mails. When the user is online, the user will have access to the data on his mail server as well as the locally stored data. However, when the user is offline, the user will only have access to locally stored data. Users may choose to log out or get logged out due to session expiry. Even when logged out, the user may access the locally stored data by clicking on Cancel on the login screen.

Download Message Setting details

By default, 30 days’s mailbox data will be available to the user for Offline access. If the user wants to download older data, he can navigate to the Local Storage setting and download it by specifying the date.

  1. Select cog iconSettings.

  2. Click Offline.

  3. Select the date in the date picker for the previous data to be downloaded.

  4. Click Apply.

The data download process will get started.

The Zimbra Desktop app is also designed to handle network error conditions. For e.g. if the message download to local storage is in progress and the network is interrupted, then the message download process will go in a paused state. The Zimbra Desktop app will resume the download process once the network connection is restored.

Local Data Storage location

Once the user’s mailbox data is downloaded successfully, each message is stored in a .eml file.

The data is downloaded at the following location on user’s desktop:

  • Windows : C:\Users\[USER-NAME]\AppData\Roaming\@zimbra\storage\[account-email-address]\.

  • Mac : /Users/[USER-NAME]/Library/Application Support/@zimbra/storage/[account-email-address]/.

Freeing up mailbox storage space

Users will have limited storage available on their mailbox. Users may free up space on their mailbox by moving some of their emails to their local storage. The emails moved to local storage will be accessible to users via the Zimbra Desktop app.

To move the emails to local storage, follow the instructions below:

  1. In Mail tab, create a folder under Local Folders.

  2. Select the mails you want to move to the local storage.

  3. Move those mails to the folder that was created under Local Folders.

Alternatively, user can utilize the Auto-Archive feature to automatically move mails from mailbox to local storage on a regular basis. Refer to Auto-Archive section to know more.

Securing your data

Zimbra Desktop app downloads user’s mailbox data to user’s desktop’s local storage. Hence, it is very important to keep the local data secured.

Zimbra recommends using disk encryption to secure this mailbox information on user’s desktop. Using such disk encryption helps protect user’s mailbox data from data theft, by rendering data stored on hard drives unreadable when an unauthorized user tries to gain access.

Zimbra suggests using operating system recommended disk encryption. Refer the following articles for more information:

Secure/Multipurpose Internet Mail Extensions (S/MIME)

Zimbra Desktop app supports S/MIME functionality. Users can send Signed or Signed and Encrypted emails to other users. The administrator will have to enable this feature and provide the user’s private certificate and recipient’s public certificate.

S/MIME feature is not available on Mobile App.

User can read or send signed and encrypted messages only when the S/MIME feature is enabled. By default the S/MIME feature is disabled for all users.

The S/MIME feature available on the Zimbra Desktop app is client-side S/MIME, and the S/MIME feature available on the Modern/Classic Web app is server-side S/MIME. To avoid confusion for end-users, we recommend not to use both of these features together.

Encrypted Emails

The Encrypted email refers to an email that has been encrypted with a digital certificate.

Encrypting an email helps to protect sensitive data and preserve confidentiality and privacy. This helps in making sure that only the intended recipient can read the email. If the email is intercepted and opened by an unintended user, that user won’t be able to decrypt and view the email.

For sending encrypted emails, users will need their Private certificate and the recipients Public certificate.

For reading encrypted emails, users will only need their Private certificates.

Signed Emails

The Signed email refers to an email that has been signed with a digital certificate.

Signing an email helps to:

  • Ensure data integrity i.e. the email was not altered from its original form.

  • Email authenticity i.e. the email came from an authentic sender.

  • Non-repudiation i.e. the signer cannot deny the authenticity of the email.

This helps in knowing that the received email message comes indeed from the declared sender (a warning appears if someone else intercepted and modified the message before it arrived).

For sending signed emails, users will need their Private certificate.

For reading signed emails, users will need the recipient’s Public certificate.

Importing certificate

In this guide we assume that the users have got the certificate from standard service providers (e.g. Comodo, DigiCert, Go Daddy, etc) whose root CA certificates are already present in browsers.

For easy understanding of the steps, we will refer to following examples throughout the section:

  • Sender’s private certificate - sender-pvt.p12

  • Recipient’s public certificate - recipient-pub.crt

Importing sender’s private certificate

Zimbra Desktop app refers to the system location for validating the user’s private certificates. Depending upon the format of the certificate, the file extension may vary. Some of the standard certificate extensions are pfx, .p12, .p7B, .sst.

Importing on Windows

There are 2 options to import the certificate on Windows.

Option #1 - Using Internet Options window.

  1. Press Windows+R to open Run box.

  2. Type inetcpl.cpl to open the Internet options window.

  3. Go to ContentCertificatesPersonal.

  4. Click on Import.

  5. Follow the instructions and provide your private certificate sender-pvt.p12 and its password when prompted.

  6. You should see a The import was successful message once the import is completed successfully.

Option #2 - Using certificate manager window.

  1. Press Windows+R to open Run box.

  2. Type certmgr.msc to open certificates management window.

  3. On the left hand side, right-click on Personal and go to All TasksImport to open the certificate import wizard.

  4. Follow the instructions and provide your private certificate sender-pvt.p12 and its password when prompted.

  5. You should see a The import was successful message once the import is completed successfully.

Importing on Mac

  • Importing Private certificate:

    1. Double-click on private certificate sender-pvt.p12.

    2. Grant access to the system keychain.

    3. Follow the instructions and provide the certificate password when prompted.

    4. The certificate is added to system keychain

  • Set the trust level of the certificate:

    1. Double-click on the added certificate sender-pvt.p12 in the system folder.

    2. Select the 'Always trust' option in the trust field.

  • Grant Zimbra Desktop app the access to the certificate key:

    1. Expand the added certificate in the system folder.

    2. Double-click the certificate key.

    3. Go to Access control tab.

    4. Add Zimbra Desktop app in the list of apps which have access to the key

    5. Save changes

Importing recipient’s public certificate

  1. Click [Contacts] tab.

  2. Right-click the contact and select Edit Details.

  3. In the Security Certificate section, click on Add a certificate.

  4. From the file explorer, select the recipient-pub.crt and click Open.

  5. Click [Save].

Sending 'Signed' or 'Signed and Encrypted' emails

  1. Compose a new message.

  2. Add a recipient in the To field.

  3. At the right-hand top corner choose an option from the dropdown. By default Do not sign or encrypt is selected.

    • Do not sign or encrypt: Mail is neither signed nor encrypted. This is equivalent of disabling the S/MIME feature.

    • Sign: Send signed message to the recipient.

    • Sign and Encrypt: Send signed and encrypted messages to the recipient.

  4. Click [Send].

S/MIME and Encryption Settings

You can change the sign and encryption preferences from Settings.

  1. Go to cog iconSettingsS/MIME and Encryption

  2. Select the preference of your choice.

  3. Click [Save].

  4. The selected option will be applicable when users compose a new message.

PST Import

PST Import feature allows users to import their emails from an existing PST file into the Zimbra Desktop app. Currently, it only supports importing mail data. If the .pst file has any Contacts or Calendar data, that will not be imported.

  1. Go to cog iconSettings

  2. Click Accounts in the left pane and choose an account from the right pane.

  3. In Import from Outlook (.pst file) section, click on Choose .pst file

  4. Choose the .pst file in the file explorer and click Select.

  5. Click Import to start the PST import.

Depending upon the file size, the import process may take time. Users will be notified once the import is complete.

The mail data is imported under Local Folders. A folder will be created by the name of the imported PST file. For e.g. if the imported .pst file name was importmail.pst, then a folder importmail.pst will be created under Local Folders. Users may rename the folder after the PST import is completed successfully.

The folder hierarchy in the PST file will be preserved in the imported folder.

PST Import feature is not available on Zimbra Desktop app on Mac.

Import failure

Sometimes importing PST files may fail due to low disk space availability. If the PST import fails, user may start the PST import process again. However, if the folder has been created then those will have to be manually deleted before starting the PST Import again.


Zimbra Desktop app provides an Auto-Archive feature which helps user move old emails from the mail server storage to the Desktop App’s Local Storage. The archived emails are not accessible through Web App but will be accessible Zimbra Desktop app.

  • Archiving regularly helps free space on your mail servers.

  • For example, if you have a 5GB quota available which gets exhausted, then you can archive your mails to free up this quota.

    • Suppose you archive mails amounting to 1GB, then these 1GB of mails will move from your mail server to your local storage.

    • These 1GB mails would be accessible using your Zimbra Desktop, but not using your webmail.

    • You will be able to access these 1GB mails even when you do not have internet connectivity, as these mails will be stored in your local storage.

  • Archiving checks for the email across all the folders/subfolders. If the primary folder and its subfolder emails matches the archiving criteria, those will be moved under Local Folders and the folder hierarchy will be maintained.

Auto-Archive will only archive emails present in your local storage. Refer to Download Message Setting details for more information on downloading the emails to local storage.

Enabling Auto-Archive feature

Auto-archive feature is disabled by default.

Following are the steps to enable it:

  1. Go to cog iconSettings

  2. In GeneralStorage, select the Enable checkbox.

  3. By default mails older than 30 days will be archived.

  4. To change the days, update Auto-archive emails older than textbox field.

  5. Click Save.

To start the archiving of messages, Zimbra Desktop app needs to be restarted.

Any changes to Auto-Archive settings will be reflected only after restarting the Zimbra Desktop app.

Supported Zimlets in Zimbra Desktop app

Zimlets are not available when the Zimbra Desktop app is Offline.

Following Zimlets are available in Zimbra Desktop app when it is Online.

  • Jitsi: Zimlet to add a Jitsi video conferencing link to an event.

  • Video Call preferences: Allows the user to define video call providers to use in the Calendar.

  • Slack: The Slack zimlet helps to connect user’s Slack account to Zimbra for quickly initiating conversations using Slack.

  • Date Zimlet: Detects dates in emails or other content and displays list of the day’s event on hover.

  • User Feedback: Adds an option in cog icon to provide product feedback to Zimbra.

  • Additional Signatures: Allows user to make extra signatures to use with any accounts.

  • Restore Contacts: Restore contacts from previous backup. Restore from backup option is added in ContactsSort Dropdown

  • Calendar Subscription: Adds Subscribe option in CalendarOthers to subscribe to external calendar feeds.

Following Zimlets are not available in Zimbra Desktop app when it is Online. However these zimlets can be accessed via Zimbra Modern Web App.

  • Dropbox

  • Google Drive

  • OneDrive

  • Zoom

Upcoming features in Zimbra Desktop App

Upcoming features planned for the future releases of Zimbra Desktop App are:

  • Offline support for Calendar

  • Offline support for Contacts

  • Backup and Restore

  • Enhanced Search

  • Offline support for documents in user’s Briefcase

And many more…​.

Known Issues

  • User might very rarely encounter a white-screen followed by Zimbra Desktop app becoming unresponsive. Even if user encounters such a situation, no data is lost. As a workaround, user may try the following workarounds:

    • Click on Edit→Reload

    • Restart the Zimbra Desktop app

    • If the app becomes unresponsive without showing the white-screen, users may to switch to Message View instead of the 'Conversation View'

  • Customers who are on Kepler-Patch-24 or Joule-Patch-31, would have users face issues during logging into the Desktop App. They can wait for the next patch Kepler-Patch-25 or Joule-Patch-32 for this issue to get resolved or use a workaround.

Workaround - Admin needs to set the zimbra_same_site_cookie variable to null. Commands to be used on CLI:

zmlocalconfig -e zimbra_same_site_cookie=""
zmmailboxdctl restart
  • In Offline mode, only partial (cached) Contacts and Calendar data is available to the users.

  • When user is Offline and enters any text to search, the Invalid Search, please try again error is displayed. When Offline, only the following keyword based search is supported - from, to, cc, subject, in, has, date. Other search parameters provided in the following list will be implemented as a part of product roadmap - http://docs.zimbra.com/desktop7/help/en_US/Search/query_language_description.htm.

  • When a user sends a Signed/Encrypted email containing inline images added through the Insert Images option in the toolbar, the images are not displayed to the recipient.

  • Users will not able to set the Zimbra Desktop app on Windows Operating System as the default mailto App.

  • Share and Meeting action buttons don’t appear on the emails when they are moved to a Local Folder.

  • When users move a message which has a signature containing an image, from Inbox to a local folder, the image is lost.

  • When the user replying to a Signed message which contains an inline image and changes the S/MIME setting to Do not sign and encrypt, an error is encountered and the mail is not sent.

  • On Mac OS, when sending a Signed or Signed and Encrypted message, the email address of the sender is not displayed along with the message type. Only the message type like Signed or Signed and Encrypted gets displayed.

  • Errors are encountered when a user who does not have a valid certificate tries to Reply/Reply-All/Forward/ a Signed or Signed/Encrypted message.

  • If a user creates contact with multiple email addresses and tries to upload the certificate which has only 1 matching email address in the contact, an error is encountered and the certificate upload fails. The workaround is to create a contact with a single email address matching the certificate.


Why do I get an Invalid Zimbra Server error when I specify the Zimbra Server URL while trying to log into the Zimbra Desktop App for the first time ?

The Zimbra Desktop app is designed to do validations when users provide a Zimbra Server URL in the textbox. Before the user proceeds to the login page, it checks if the URL provided is of the valid Zimbra Server.

Users can check:

  • If the Zimbra Server URL is accessible from the system by specifying the URL in Web Browser.

  • Check if the Zimbra Server URL is correct.

Why can’t I see my emails when offline?

Users may not be able to view emails offline because emails have not been downloaded to their local storage.

Users can check:

  • Date under cog iconSettingsOffline: If the emails that user is looking for are from a date earlier than the date provided in the Date picker in Offline Settings, then the user will have to select the appropriate date to be able to view those emails offline.

  • Data download aborted due to errors: There is a possibility that the user initiated data download was not completed successfully. Users can go to cog iconSettingsOffline and check for error messages, and re-initiate the download.

I got logged out due to session expiry, can I still access my emails downloaded to local storage?

Yes, click Cancel on the login screen to access the emails from the local storage.

Why can’t I preview attachments when offline?

There are some functionalities that are not available when the users are Offline. Refer to Offline Functionality section for more details to see which functionalities are available and which are not available when users are Offline.

When does the download of mails start?

When you install the Zimbra Desktop app and login into your account for the first time, the app will start downloading the last 30 days of mails to your local storage immediately. The time taken for this download to complete may vary depending upon the amount of data that you have available in the last 30 days, your internet connection speed, and the server availability.

How do I know if the app is downloading mails?

When the app is downloading emails to your local storage, you can see a Downloading label in the cog iconSettingsOffline tab.

Do I see the mails downloaded to my local storage separately in my mailbox?

No, you will not see the mails downloaded to your local storage separately in your mailbox. Mails stored locally and mails not stored locally appear together in your mail folders. The user experience is designed to be seamless for the end user. So, for example, if my Inbox has mails which are up to 1 year older, and I have set my cog iconSettingsOfflineDownload data back to configuration for last 30 days, then even after mails have synced to local storage, the user will see all the mails dating past 1 year in the Inbox. If the user loses internet connectivity and goes offline, then Inbox will display mails which are in his local storage i.e. only the mails dated 30 days ago.

Are the mails downloaded to local storage removed from my mail server?

No, the mails downloaded to local storage will not be removed from the mail server. They coexist on mail servers as well as local storage. The mails will only be removed from the mail server if the user has enabled the Auto-Archive feature.

Will the mails in my local storage also be available on my web mail?

Yes, the mails in your local storage also be available on your web mail. Since the mails co-exist on mail server as well as local storage, they will be available on your web mail as well. However, if the Auto-Archive feature is enabled, then the web-view and Desktop-view of your mailbox will differ.

How do I know if my emails are being auto-archived?

Once the Auto-archive feature is enabled, Zimbra Desktop App will have to be restarted to start the auto-archiving of the mails. Depending upon the data to be archived, the process may take some time. The mails matching the auto-archive criteria will be moved from Inbox to Local Folders. If mails from multiple folders or subfolders are archived, then the folder hierarchy will be also maintained under Local Folders.

I enabled the Auto-archive setting, but my mails are not getting archived, why?

There are multiple reasons why it might appear that auto-archiving is not working.

  • Auto-archive feature is disabled by default, please check if you have enabled the feature from cog iconSettingsGeneralAuto-archivingEnable.

  • Whenever you start your Zimbra Desktop App, it starts downloading the latest mails to your local storage as per the date provided in the cog iconSettingsOfflineDownload data back to setting. This process is called the offline-sync process. If auto-archive feature is enabled, the auto-archive process will start only after the offline-sync process gets completed, i.e. all mails as per the offline criterion have been downloaded to the local storage. Please wait for the offline-sync process to complete and check again.

    • If offline-sync is already completed, please try re-starting the app.

  • Auto-archive will only run on locally stored emails. Please check if the date provided under cog iconSettingsOfflineDownload data back to is older than the days provided under cog iconSettingsGeneralAuto-archivingArchive mails older than. For example, if today’s date is 1st January 2021, and

    • if cog iconSettingsOfflineDownload data back to = 1st January 2020

    • then, cog iconSettingsGeneralAuto-archivingArchive mails older than should have value less than 365 for auto-archive to work.

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