I have been running Sandboxie 5.33.2 for a while under Windows 7.
Also running the latest Firefox and Thunderbird.
Up until a few months ago I had NO problems with Sandboxie and Thunderbird. Been using them together for several years.
I am one of Sandboxie's first customers and have a lifetime account.
I reported the links to Firefox/Chrome failing in a forum entry here several months ago and nothing has changed.
In addition to the links failing to execute in both Firefox and Chrome, I have been frustrated with Thunderbird (Roadrunner mail) doing strange things.
Many of my "sent" emails do not show up in the Sent folder and many incoming emails are missing.
NOTE: All my received emails are also sent to my gmail account via roadrunner forwarding so I am able to see that many incoming emails do not get to my sandboxed Thunderbird.
Or they show up then disappear. I fear Sandboxie has been abandoned.
Note; My Sandboxed Firefox works fine with no problems, but Thunderbird was driving me crazy.
I switched back to UN-Sandboxed Thunderbird a few days ago and am currently NOT having any problems..
NOTE: These issues have been going on since Sandboxie version 5.30 or so, and through several updates to Firefox and Thunderbird.