I think GPG4Win (great software by the way), does not handle attachement sizes correctly.
I’m using:
-Windows 10 21H2
-Office Professional Plus 2021
-GPG4Win 4.0.2
I have two machines that are identical in that regard, that are however not mirrored otherwise and have different software and settings, that’s why I’m somewhat sure I found an actual error.
The problem:
If I create an E-Mail that requires attention from GpgOL, no matter if encrypted or just signed, if the E-Mail attachements exceeds a certain size, GpgOL prints:
“The mail exceeds the maximum size GpgOL can handle on this server”
and gives a list of the files it proceeds to ignore. Other E-Mail applications supporting OpenPGP handle the mail just fine.
The funny and confusing thing is, I can create said E-Mails wit GpgOL without a problem, encrypting, uploading, sending, no errors.
But If I go back to read the E-Mail either in “Sent” or “Inbox”, I get the error message.
I can however circumvent the problem by following this guide from Microsoft (https://docs.microsoft.com/en-us/outlook/troubleshoot/message-body/attachment-size-exceeds-the-allowable-limit-error) regarding increasing the standard attachement size.
So, to be more precise it is an error in the communication between Outlook and GpgOL I think.
If I send the same files unencrypted, Outlook handles it fine.
If I raise the Outlook limit, GpgOL works as intended.
However, hacking the registry should not be expected by the average user.
