Hello,
What type of email account are you using? IMAP, POP3 or Exchange?
Are you syncing Outlook with any other device (such as a mobile phone or another computer)? If so, we may try to temporarily disable the sync and then see if this issue continues.
In addition, we may also try to start Outlook with /cleanviews switch to see the result. This command will reset your custom folder views to the default and you will recreate your custom views after running the command. To run the command,
press Windows key + R to open the Run command, type outlook /cleanviews and press Enter.
Please let me know the result.
Regards,
Steve Fan
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