Except for where it coincides with previous editions. It's so new and still so changing, that works one day, may not work the next. An example, after I got the full RTM upgrade build 10240, and it was activated, for no reason I could determine, it became unactivated. I had my copy as Preview Builder, so no former Win7sp1 or win8.1 to revert to. Instead I went back to build 10166 which was activated, then added the newest update again. I made sure to put a copy of the VDI (virtual box hard drive) that I had it installed into. That held a few days and then it did it again! I tried the same thing of going back to 10166 and then back up to the newest update. This time it didn't work. Same exact procedure which worked a week before failed to do so again. Predictable? I think not!
Instead I restored a copy of the VDI file, lost what I'd done in the meantime to the one that was there and was "activated" again. This is one reason why I prefer using Linux for my main system and consider "activation" as a Microsoft generated "virus".
For now, what may work one day in win10 may not work the next, so nobody's an "expert" on it, till it's settled down more.
I have a PC, and have been using Windows-7 until today, when I started using the free Windows-10 instead.
One huge problem is that Windows-10 changed all my documents to "Read-Only."
(Regarding my documents, I use "Microsoft Office Word 2007," which has been working great, and I use it daily!) What can I do to fix this situation?

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