Hi @Valentin ,
Welcome to our forum!
Would you mind offering me more information for further analysis:
- Whether you cannot copy all attachment or just specific ones.
- If adding your account to another Outlook client, whether the issue will appear.
Given this case, it is recommend you use the followig troubleshooting:
• Check the version of the Outlook client(File > Office Account > About Outlook), and make sure that you upgrade it to the latest(File > Office Account > Update Options > Update Now)
• Sometimes addins may also lead to the error, run outlook in safe mode: Win+R, type outlook.exe /safe.
• If above doesn't help, try creating a new Outlook profile by following these steps:
Open Control Panel > Mail > Show profiles > Add a new profile and connect your account to see if the issue continues.
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