You can do a malware scan, just to be sure.

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware

You can use the MSConfig program or the Autoruns utility to see what software is getting started (be careful with disabling services).

• https://docs.microsoft.com/en-us/sysinternals/downloads/autoruns

Thanks for the reply. I have already scanned for viruses and malware and nothing has come up. I'm not sure what you mean by seeing what software is getting started, so I would appreciate it if you could elaborate. I have already done a clean boot and Firefox still will not open in a clean boot environment.

Your Microsoft account may have parental controls enabled which limits what browsers you can use, try creating a new local user account.

Also try renaming firefox.exe to something else but note that this will break DRM protected videos.

Your Microsoft account may have parental controls enabled which limits what browsers you can use, try creating a new local user account. Also try renaming firefox.exe to something else but note that this will break DRM protected videos.

Thank you, the parental controls issue was exactly it. I have had this account since childhood and while most of the restrictions have since been removed, I recently had to go into Microsoft family settings to remove one that I had forgotten to remove, and in the process I may have accidentally enabled blocking unsafe browsers. I appreciate the help!