Cannot open some Emails (.msg) with outlook

we are currently experiencing issues while opening certain emails.

Error Message

We save and archive mails via Outlook 365 in the file system as .msg files. Now, when opening one I get an error: “… cannot be opened. File might be opened or you do not have permissions”.

This seems very odd. We use a Synology as our NAS. I can open other files too, the described problem only occurs in some places.

What we tried

  • manually copied the same file to a different place via the File Station by Synology…and was able to access the file
  • Mounting the Drive not via Netdrive, but as a smb network drive in explorer (same credentials) - we could open the file


  • Synology DS718+
  • Netdrive 3 connected via WebDav
  • Mailapp: Outlook 365

I am not seeing anything obvious in the logs and have no clue how to fix this issue.

Dear kohler1,

Thank you for using NetDrive.

After setting the log level to VERBOSE, please reproduce the problem and send us the debug log file :

There is no login related credential information in the log files.

Sorry for the inconvenience it may caused.


This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.