What clearing Outlook cache actually does

Clearing your Outlook cache removes temporary files that Outlook stores on your computer to speed up searches and load messages faster. These files pile up over time and can take up gigabytes of space, slow down your program, or cause Outlook to freeze or crash when the cache becomes corrupted.

The cache is separate from your actual email — deleting it will not erase any messages, contacts, or calendar events. Outlook rebuilds the cache automatically the next time you open the program, so you are just clearing out the temporary junk that got in the way.

Key Takeaways

  • Outlook cache is temporary data stored on your computer that speeds up the program but can grow large enough to cause crashes or freezing.
  • Clearing the cache does not delete your email, contacts, or calendar — only the temporary files Outlook uses to run faster.
  • The steps differ depending on whether you use Outlook on Windows, Mac, or the web version, and whether you have Outlook 2016 or a newer subscription version.
  • After clearing the cache, Outlook will rebuild it automatically, which may take a few minutes the first time you open the program.
  • If Outlook still crashes or freezes after clearing the cache, the problem may be a corrupted data file rather than the cache itself.

How to clear cache in Outlook on Windows

The fastest way on Windows is to close Outlook completely, then delete the cache folder from your computer's hidden files. Open File Explorer and paste this path into the address bar: %localappdata%\Microsoft\Outlook. Press Enter and you will see a folder called RoamingCache — delete this entire folder.

If you cannot find RoamingCache, your Outlook version may store cache in a different location. Try this path instead: %appdata%\Microsoft\Outlook. Look for a folder named OfflineAddressBook or any folder with a long string of numbers and letters — these are cache files. Delete them, then restart Outlook.

If you are uncomfortable navigating hidden folders, you can clear cache through Outlook itself. Open Outlook, go to File > Options > Advanced, scroll down to Outlook Data Files, and click Empty Deleted Items Folder. This clears one type of cache but not all of it, so the folder method is more thorough.

How to clear cache in Outlook on Mac

On Mac, close Outlook completely first. Open Finder and press Command + Shift + G to open the "Go to Folder" dialog. Paste this path: ~/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles. Press Enter and look for a folder with your email address or a numbered profile name.

Inside that folder, find Data and open it. Look for files named OfflineAddressBook or folders with long names — these are cache files. Delete them, then restart Outlook. The program will rebuild the cache the next time it opens.

If that path does not exist on your Mac, try ~/Library/Preferences and delete any file starting with com.microsoft.Outlook. This is more aggressive and will reset some Outlook settings, but it clears all cache files at once.

Clearing cache in Outlook on the web

If you use Outlook.com or Outlook accessed through a web browser, you do not have a cache folder to delete on your computer. Instead, clear your browser's cache. The steps depend on which browser you use.

In Chrome, press Ctrl + Shift + Delete (or Command + Shift + Delete on Mac), select All time from the time range dropdown, check Cookies and other site data and Cached images and files, then click Clear data. In Edge, press Ctrl + Shift + Delete, select All time, check the same boxes, and click Clear now. In Firefox, press Ctrl + Shift + Delete, select Everything, check Cookies and Cache, then click Clear Now.

When to clear cache and what to expect

Clear your Outlook cache if the program is running slowly, freezing, or crashing regularly. You should also clear it if you have not done so in several months and your Outlook folder is taking up more than 500 megabytes of space. Check folder size by right-clicking the Outlook data folder and selecting Properties on Windows, or Get Info on Mac.

After you delete the cache, Outlook will take a few minutes to rebuild it the next time you open the program. During this time, searches may be slow and your inbox may take longer to load. This is normal and only happens once. If Outlook still crashes after the cache is cleared, the problem may be a corrupted data file, and you may need to repair your Outlook data file or reinstall Outlook.

Difference between cache and Outlook data files

Cache and your actual Outlook data files are two different things. Cache is temporary — it speeds things up but can be deleted without losing anything. Your data files contain your actual email, contacts, calendar, and tasks. These are stored in files with names like Outlook.pst or Outlook.ost and should never be deleted.

If Outlook is crashing and clearing the cache does not help, the problem may be a corrupted data file instead. You can repair a data file in Outlook by going to File > Options > Advanced > Outlook Data Files, selecting your data file, and clicking Open File Location. Then close Outlook and run the Outlook repair tool (called ScanPST.exe on Windows) on that file. This is more complex than clearing cache, but it fixes problems that cache clearing cannot solve.

Frequently Asked Questions

Will clearing the cache delete my emails?

No. Cache is temporary data that speeds up Outlook. Your actual emails, contacts, and calendar are stored in separate data files that clearing the cache does not touch. You can safely delete the cache without losing anything.

How often should I clear my Outlook cache?

Most people do not need to clear cache more than once or twice a year unless Outlook is running slowly or crashing. If you use Outlook heavily and notice performance problems, clearing cache every few months may help. There is no harm in clearing it more often.

What if I cannot find the cache folder?

Cache folder locations vary by Outlook version and Windows setup. If the paths listed above do not work, try searching your computer for "RoamingCache" or "OfflineAddressBook" using File Explorer's search box. You can also clear cache through Outlook itself by going to File > Options > Advanced, though this method is less thorough than deleting the folder directly.

Does clearing cache speed up Outlook?

It can, especially if the cache has grown very large or become corrupted. A fresh cache often loads faster than an old one. However, if Outlook is slow for other reasons — like a slow internet connection or too many add-ins — clearing cache will not fix those problems.

What should I do if Outlook still crashes after clearing the cache?

Try repairing your Outlook data file using the ScanPST tool on Windows or the Inbox Repair Tool on Mac. If that does not work, try disabling Outlook add-ins by holding Ctrl while opening Outlook, or reinstall Outlook entirely. Persistent crashes are usually caused by corrupted data files or conflicting add-ins, not the cache itself.