What OS? I almost never close out of Firefox on my Macs at home and I've never seen that message there. FF on Windows seems to be the same. It's been ages though since I've left FF open for months on end on Linux though.
I've had this same experience on Linux Mint. I'll run apt update & apt upgrade and, occasionally, if Firefox is one of the things being updated, new tabs and new pages won't load and will tell me I need to do a system restart to continue browsing.
I always update manually, so it never happens without me initiating the update first. But sometimes I'm like, "Dangit, didn't realize this update would require a restart to keep using Firefox."
On Linux, disabling Firefox updates in Firefox itself will not fix this issue, because Firefox's own updater doesn't actually have this bug! You get this warning when the Linux package manager has already replaced the files underneath the running program.
You say it's windows, but I think you said it's a work machine so maybe they're updating firefox from under you?
Restart Firefox to let it finish updating. I don’t think I’ve ever seen a screen that says you HAVE to restart right now at this very moment.
When it happens, it doesn't let me do anything other than stay on the already loaded webpage without restarting.
Open a new tab > "Restart to continue..."
Click a link > "Restart to continue..."
Type a URL > "Restart to continue..."
and etc
What OS? I almost never close out of Firefox on my Macs at home and I've never seen that message there. FF on Windows seems to be the same. It's been ages though since I've left FF open for months on end on Linux though.
I've had this same experience on Linux Mint. I'll run apt update & apt upgrade and, occasionally, if Firefox is one of the things being updated, new tabs and new pages won't load and will tell me I need to do a system restart to continue browsing.
I always update manually, so it never happens without me initiating the update first. But sometimes I'm like, "Dangit, didn't realize this update would require a restart to keep using Firefox."
Windows 10
Same on MacOS
It happens on Linux – after your package manager has updated Firefox. Which typically means that you told it to. So it's not really a surprise.
They said at work, perhaps it is a corporate thingy that forces them to be on the mandated version.
I got it again unfortunately, here's a screenshot of what it looks like
I found this. https://superuser.com/questions/1451210/how-can-i-make-firefox-stop-forcing-me-to-restart-my-browser
You say it's windows, but I think you said it's a work machine so maybe they're updating firefox from under you?