It was a biggie. When it was done, I had to answer loots of questions asking for my permission to share data with them.
I loaded Firefox when it was all done, and found that all my bookmarks, saved passwords etc had gone. I had a new profile. I went through the "switch profile" optiomn to get it to use my old profile, but it wouldn't cooperate.
Was it the Windows update that had done this, or had it coincided with a Firefox update perhaps?
I tried a couple of other programs. Some worked, some decided they needed to be configured for Windows.
I was very, very cross. I am very very cross.
That wasn't getting anything resolved though, so I pushed my annoyance to one side, rolled up my sleeves, and looked at what options I had.
My last Mozbackup was a couple of months ago, so I knew I could restore that. But I'd been busy tidying up, ready for my next backup which is (or was going to be) in a couple of days.
I googled for some options. I tried forcing Firefox to use my old profile, but it didn't like it.
In the end, I had to find out what the elements were that I needed, and I copied them from the old profile to the new. I needed more elements than I had realised.
So, I've spent a couple of hours in total and I'm now back to where I should have been at 8.30 this morning.