Offline Mode Configuration from Admin Console in G Suite
As a G Suite administrator, you can control whether users in your organization can access their Google Docs, Sheets, Slides and mails when their computers, mobiles or tabs aren't connected to the internet. By default, offline access is enabled for organizations
As a G Suite administrator, you can control whether users in your organization can access their Google Docs, Sheets, Slides and mails when their computers, mobiles or tabs aren't connected to the internet. By default, offline access is enabled for organizations, and admins can turn it on or off for their domain as needed.
Work offline in Gmail
When internet access is unavailable, you still can read, write, search, delete, and label email messages by enabling Gmail offline mode. Later, when you have access to the internet, Gmail automatically updates and sends messages in your outbox and downloads updates from the server.
By default, Gmail stores the last 30 days of mail, including attachments whereas spam and trash are not stored. To work in offline mode of Gmail, you need the latest version of the Chrome browser, version 61 or later.
Enable Gmail web offline for your domain
G Suite administrator must enable offline capabilities for your domain before users can turn on Gmail offline in their Gmail settings.
From the Admin console click Home page, go to Apps > G Suite > Gmail > User settings.
Scroll down to the Gmail web offline.
Check the Enable box Gmail web offline.
If you want offline data deleted for all users when they sign out of their Google account, then check the Force deletion of offline data on log out of Google account box.
Then click Save. It may take an hour for changes to propagate.
Have users enable Gmail offline
Users who want to work offline need to make changes by enabling Gmail offline in their Gmail settings.
Go to settings and click the Offline tab.
Check the Enable offline mailbox.
Under the Security section, select one of the following to indicate how to handle offline content when you sign out of your Google account. Keep offline data on your local device. Data stored on your device will not be deleted when signing out of your Google account or changing your password. To delete data of your Gmail Account from your device disable offline mail and save changes.
Remove offline data from my computer. Data will need to be resynced to your computer when signing back into Gmail Account. It may take a few hours to resync the mailbox.
Click Save changes.
Open Gmail offline
Work in Gmail offline from Chrome in the following ways:
Create a bookmark for your inbox mailbox, and then use the bookmark to open Gmail when you're offline.
When you don't have access to the internet connection, open a Chrome browser window and type mail.google.com.
Set offline preferences
By default, Gmail in offline mode stores the latest 30 days of email and attachments on your local device, and Chrome allows Gmail to use up to 7% of your available hard drive space for offline data. To reduce the amount of storage space your offline data uses, uncheck the Download attachments box in Sync settings or reduce the storage duration to 7 days.
Go to Settings in Gmail and Click the Offline tab.
Choose a value in Sync settings.
Values are 7, 30, and 90 days.
Click Save changes.
Offline capabilities stop working
If a G Suite admin disables Gmail offline for a domain, it becomes unavailable to users, even if they've enabled it in their Gmail settings.
Gmail offline services only work when Gmail is open in one tab, close any additional tabs running Gmail.
Gmail won’t open or quits unexpectedly
If Gmail won’t load or stops working then try clearing your browsing history.
Gmail offline is out of storage space
If your mails contain a large number of attachments, uncheck the Download attachments box in Sync settings and reduce the storage duration to 7 days.