Posted by on March 19, 2013

I had an Outlook 2010 client today that would crash every time the user tried to send an email, click Check Names (ctrl-K), or update the offline address book. Sending or checking names would generate the typical Windows 7 error message saying, “Microsoft Outlook 2010 has stopped working. Windows can check online for a solution…” Attempting to download the offline address book just caused Outlook to stop responding.

The solution was to start Outlook with the CleanAutocompleteCache switch:

Outlook.exe /cleanautocompletecache


  1. ac
    April 25, 2013

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    this solution works on outlook 2013, thanks!

  2. Raymond L
    August 9, 2014

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    I’m glad to hear a solution for 2013 has been found but how does an “average Joe” (non-techie) like myself, implement this fix?

  3. jay c
    August 10, 2014

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    Hi Raymond.

    First, make sure that Outlook is not running. Then, on Windows Vista or 7, click on the Start button and type “outlook.exe /cleanautocompletecache” then press Enter.

  4. Gordon
    August 28, 2014

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    Thanks – solved the problem that has been annoying me for ages!

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