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This problem is not associated with any of the security patches so there is no need to uninstall them if Outlook will not launch. Outlook will automatically look for the fix on launch, so if this issue persists through multiple launches please use Outlook Web Access (or your providers webmail interface) for an hour then try again. A fix has been published but will take time to propagate to worldwide availability. There is a new symptom of Outlook crashing on launch starting on. Now on the Office support site, Microsoft says: Additional details can be found under EX218604 in the admin center. Please note, users may need to restart the Outlook client to enable the fix. We've completed the fix rollout and confirmed via internal monitoring the service has recovered. Additional details can be found in the admin center under EX218604 and OL218603. As a workaround, users can utilize Outlook on the web or their mobile clients. We're investigating whether a recently deployed update could be the source of this issue.
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On Twitter, Microsoft used its Microsoft 365 Status account to keep users updated:
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The company does say, however, that none of the update release on this particular date are to blame. While Microsoft has not indicated which update it believes may have been to blame, the crashing issues only started on 15 July.
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