- Getting errors while working in Microsoft Exchange can have a lot of implications, especially if the issue isn't resolved in a timely manner.
- To start fixing this issue, disable and enable MAPI, and check if the Outlook synchronization is set up properly.
- If you want to check out some other useful guides for Email clients, visit our detailed Email Hub.
- For more easy-to-follow Exchange guides, don't hesitate to visit our Microsoft Exchange page.
Outlook may not synchronize at times if you’re using a Microsoft Exchange account if it was not set up properly.
Users trying to synchronize a Microsoft Exchange Server mailbox with an offline folder (.ost) file in Outlook will receive this error message:
Cannot start Microsoft Outlook. Cannot open the Outlook window. The set of folders cannot be opened. You must connect to Microsoft Exchange with the current profile before you can synchronize your folders with your Outlook data file (.ost)
How do I fix Outlook not syncing with Microsoft Exchange?
1. Disable and enable MAPI
- Head over to the Exchange admin center official Microsoft page
- Log in with your Microsoft Exchange account, then select Recipients > Mailboxes
- In the mailbox list, choose the mailbox that you need to modify
- Select the mailbox properties page, then choose Mailbox features
- Under Email Connectivity, you can check the MAPI status
- If it’s enabled, click on the Disable button, then select the Enable button
- If it’s disabled, click on the Enable button, then select the Disable button
2. Check if Outlook synchronization is set up properly
- Open your Outlook app, then click File, and select Account Settings
- Choose Account Settings again, then select the Exchange or Microsoft 365, and click Change
- At the Offline Settings section, make sure that Use Cached Exchange Mode is checked
- For Microsoft 365 subscribers, at Offline Settings, also enable Use Cached ExchangeMode to download email to an Outlook data file
- Close the settings and the Outlook app, then restart the app
- Your Outlook account should now be synced properly with Microsoft Exchange
3. Set your Outlook folders to synchronize automatically
- Head over to the Tools menu, then select Options
- Under the Mail Setup tab, take a look at the Send/Receive section
- Make sure that Send immediately when connected check box is checked
- Click on Send/Receive, then in the Send/Receive pop-up, select the Perform an automatic send/receive when exiting
- Click Close, then select OK
4. Create a new .ost file if the old one is damaged
- If your Outlook folders are syncing properly, except the Inbox, it may be due to a faulty .ost file
- Head over to your left-corner Windows 10 Taskbar and under the Search box, type For Files or Folders
- Select the first option and on the All or part of the file name tab, type *.ost
- Select your SSD in the Look in list
- Next up, at the More advanced options section, make sure that Include subfolders is checked, then click Search
- The .ost file will show up in the Name column
- Right-click on the .ost file, then select Rename and choose another name and extension for it (for example .old)
- Save the new file name, then open up Outlook
- Head over to the Tools menu, then to Send/Receive, and select the Send/Receive All option
- A new sync status will be displayed on the bottom right side of your screen with the new .ost file
By following these steps, you should no longer have any issues when connecting to the Microsoft Exchange server anymore. Let us know which of the methods helped you by leaving us a message in the comments section below.
Frequently Asked Questions
There are numerous ways you can fix any delivery issues between you and recipients, most of which we’ve covered in this detailed guide.
The RPC Client Access service provides data access through a single, common path of the Client Access server, with the exception of public folder requests, which are still made directly to the Mailbox server.