Mozilla Firefox dont start properly (no windows) while sandboxed

Question

Hello everyone, 
 since a few weeks now i have a strange problem and nothing worked that ive tried. 
 Im using Windows 10 64-Bit (1903 since today; but problem also was here with 1809), Mozilla Firefox 67.0.1 64-Bit (but problemw as also there with earlier versions) and Sandboxie 5.30. 
 Problem stil exists even with disabled Add-ons and after deinstallation/reinstallation of FF. 
 I start FF either from Sandboxie (Start Web browser) or directly (setting is "start always in Sandbox). I can see in task manager that there are several FF processes; but i dont see the FF GUI. Outside of Sandboxie FF starts without a problem. 
 Sometimes, when i have started FF outside Sandboxie suddenly something will be opened in FF sandboxed (maybe i clicked a link in a different application). 
 Any ideas? 
 Greetings 
 
 Thomas

Thomas Wallutis · Accepted Answer

Hi, 
 it seems that the Exploit Protection in GDATA is the problem here. When i deactivate it, the problem vanishes. 
 Greetings 
 
 Thomas

Barb@Sophos · Answer

Hi Thomas, 
 Third party software, such as AVs, may interact with Sandboxie, it is not strange unfortunately. 
 Here's the known conflicts AV section (the forums links won't work, but you can see suggestions for troubleshooting and what to add to exclusions) : https://www.sandboxie.com/KnownConflicts#Anti-virus%20Related 
 Give that a try, there are several entries per AV, I would suggest you try the exclusions route first. You may want to reach out to your AV software support for suggestions as well, now that we have determined that your AV is blocking it. 
 Regards,