Hey everyone,

We are having a weird issue on one of our employees machines (Windows 7 Pro x64).

When sending PowerPoint attachments in Outlook 2010 (Using an internal Exchange server) from this particular computer, recipients on the outside of our network have trouble opening or viewing these files but when sent internally they can be opened fine. Again, it appears to be just this machine and I'm looking into it now. 

I was just curious if anyone's seen this before or has any ideas as to what it might be?

Any help is apprec

Hi,

First please detail "have trouble opening or viewing these files", any symptoms or error messages? Are the attachments actually changed in size and extension?

Please test from OWA to send the attachments to external on that machine, check if the problem persists.

I wonder if any local add-ins or other programs did "something" to the attachments, please do the following troubleshooting steps:

1. Disable anti-virus program and firewall on that machine, then send the attachments to test the result.

2. Run Outlook in Safe Mode to determine whether 3rd-party add-ins are the culprit:

Press Win + R and type outlook.exe /safe in the blank box, then press Enter.

If theres no problem in Safe Mode, disable the suspicious add-ins to verify which add-ins caused this issue.

Regards,

Melon Chen
TechNet Community Support