How To Fix When Outlook Not Syncing Properly

Are you having problems with the emails when Microsoft Outlook not syncing with the Exchange server? If this is the case, you may not be able to send, receive or even download any new email. 

Moreover, you could see an error message “Cannot start Microsoft Outlook” while trying to synchronize your mailbox with the .ost file. You might locate this file in the offline Outlook folder.

Often, a corrupted “.ost” file can create the issue in the email synchronization. However, you can fix Outlook’s syncing issue with some easy methods.

Things to Try if Outlook Not Syncing Somehow

You may have multiple accounts connected to the Outlook server but, the problem might occur with one email profile. Hence, before applying any repairing trick, make sure if there is any problem with your mailbox.

Basic Things to Look for

First, you should check the junk emails for any missing email in particular. In addition, you should check whether your inbox is full. If it’s showing full, no new message will arrive until you free up some space. So, clean your inbox or check other tabs for the missing emails. 

Besides, you can also take a look at the email filtering section to see whether any sender is blocked. If everything is alright, follow the below-mentioned tricks in order to fix the problem when Outlook not syncing on your system.

Trick #1: Verify Cached Exchange Mode is Enabled

If there is a difference between the number of items in the server folder and the offline Outlook folder, verify the profile settings. We have shared the steps below with which you can verify the same.

  • Click on the File tab after opening Outlook.
  • Choose “Account Settings” and then switch to the “Email” tab.

Note: Before tapping on the “Email” tab, click on “Data Files” and check whether the affected email is your default one. If it is not, select the particular email and click on “Set as default”.

  • Now, select the email and click on the “Change” option.
  • In the new window, make sure the box next to “Use Cached Exchange Mode” is checked. Press the OK button.

Close every application after this and relaunch Outlook. 

Trick #2: Clean “Sync Issues” Folder in Outlook

By applying this method, you can delete all the messages from the “Syns Issues” folder. But, after that, you would be able to recover all the emails from the server. The step-by-step instructions to clean the folder is mentioned below.

  • Click on the folder icon located at the bottom-left corner of the Outlook window.
  • Move to the “All Outlook Items” tab and look for the “Sync Issues” folder in the list on the left panel.
  • Tap on the “+” icon next to the folder to expand it. Here, you will find three folders “Local Failures”, “Conflicts”, and “Server Failure”.
  • Delete all the items from the three folders. Make sure to clean those messages from the “Deleted Items” folder also.

Restart Outlook and recover all the deleted emails by clicking on the “Recover Deleted Items From Server” option under the Home menu. Thereafter, follow the on-screen instructions to complete the recovery process.

Trick #3: Check if Auto Synchronize is Enabled

The synchronize process is a built-in feature of Microsoft Outlook. Hence, to avoid the situation when Outlook not syncing, you must verify whether the sync option is enabled in it. So take a look at the below section.

  • Click on the “Tools” tab and choose “Options” from the menu.
  • When the dialog box will prompt, go to the “Mail Setup” tab.
  • Check if the checkbox of “Send immediately when connected” below the “Send/Receive” option is selected.
  • Also, verify that the box beside “Perform an automatic Send/Receive when existing” is checked.
  • Hit OK and close the window.

Trick #4: Use the Repair Tool

Follow the below-mentioned steps to fix the Outlook synchronization issue using the inbuilt repair tool.

  • Go to the “File” tab after launching Outlook.
  • Tap on “Info” and click on “Account Settings”.
  • Select the problematic profile and click on the “Repair” button.
  • After checking the settings in the “Repair Account” window, click on Next. You need to enable network connection while the repairing process begins.
  • You can click on the “Change Account” link after finishing the repairing process. Check the email settings on the new page and press the Next button.
  • When Outlook prompts that everything is okay, tap on “Close” followed by the “Finish” button.

We hope the above trick has worked for you and Outlook is now synced properly. But, in case the problem persists, you can follow the next trick.

Trick #5: Rebuild “.ost” File in Outlook Folder

Many users reported that when no solutions work, rebuilding the “.ost” file can fix the syncing problem in Outlook. Before that, you have to enable the “Show hidden files and folders” option from the “View” tab of “Folder Option”. This is done to ensure all the hidden files are displayed on Outlook during the syncing process. 

To try this solution, first, press Windows+R to launch the Run dialog box and type “%LOCALAPPDATA%\Microsoft\ Outlook”. In the folder after pressing “OK”, you will find “.ost” files are there. Now, you just need to rename the “.ost” file by adding “.old” at the suffix of the file name.

Note: If you get any prompt like “File in use”, then turn off Outlook application from the Task Manager.

After renaming the “.ost” file, close everything and open Outlook. This time you will get to see that Outlook is preparing for first use. Wait until all the emails get synchronized in the mailbox. 

We hope next time you won’t come across the syncing issue in Outlook if you try these troubleshooting hacks.