GpgOL Incompatible Addons
The following Outlook Addons are known to cause problems together with GpgOL.
TITUS Message Classification
Causes GpgOL not to decrypt / verify any content. Mails will be shown as empty and without crypto state. They will sometimes have the crypto icon in the messagelist.
MailStore Outlook Add-in
Version ( 188.8.131.5273 tested)
The same problem as the TITUS Addon. We do not see the "Read" event and never get the option to decrypt / verify the mail. See: https://dev.gnupg.org/T3934
PDF Converter Outlook Add-in
Google Apps Sync
Symantec Endpoint Protection
Version - Unknown.
Signed / Encrypted mails are left blank. Reported here: http://wald.intevation.org/forum/message.php?msg_id=5786&group_id=11
Microsoft Azure Information Protection
Decryption no longer works if this plugin is enabled. Encryption works.