Thanks for the A2A.
To be honest, I never had the problem for a number of reasons, for example, that I don’t use hibernation. On the other hand, based on 25 years experience, I can make some educated guesses.
My educated guess would be, that Windows for the hibernation somehow modified the boot loader and settings, to get back from hibernation, instead of booting the average way and straight forward. Because to come back from hibernation, it has to load the settings and session data. It just seems like a pretty stupid idea, to do it this way. But well, Microsoft.
The catch is, that you don’t use the default Windows boot loader and settings but Grub. And Windows doesn’t know that. So, that’s a mix that doesn’t seem to work.
So, my suggestion would be, to download an according Ubuntu live system, boot it and inside mount the and chroot into the installed system and reinstall Grub. This should get you back going.
If all the assumptions are correct, you will likely boot Windows the normal way, instead of coming back from hibernation.
1 + 1 = 2 => next time you use hibernation on Windows, this is likely going to happen again. So, do yourself a favor and either leave it up and running or turn it off entirely.
It might be slightly more tedious and take some more time. But there is barely any need for hibernation. You can save your files, restart Chromium and Firefox sessions…
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