problem with firefox running sandboxed

Hi, I recently put Firefox executable (I use Firefox portable) in Comodo sandbox-fully virtualized and on first use it was normal but after closing browser and open again, I got message “your firefox profile cannot be loaded. it may be missing or inaccessible”. Can you help me why this happened?!

Hi white31,
It sounds as if some corruption might have occurred within the sandbox.
Resetting the sandbox may solve the issue.
Reset Sandbox-Comodo Help
Please note: Resetting the sandbox will delete all data and programs that are stored in the sandbox only.

Kind regards.

After unsandboxing and resetting Firefox opens and works normally but if put in sandbox again and opening few sites, same message appears again after restarting browser. I thought some plugin might cause this and disabled all of them but it happened even without plugins. btw I use Firefox portable if this matters. Any ideas what else should I try?!

I deleted current Firefox folder and installed again and it works for now in sandbox.