Bootcamp Windows 10 memory BSoD I have run windows 10 on my iMac (late 2015, Catalina) over the last year through bootcamp with no issues. I only use it for video games. I recently built a PC for a better gaming experience and to free up space on my iMac. I am trying to retrieve my save files from the partition, but am getting a blue screen. There have been no changes made to my computer. One day I was gaming, the next day I get a blue screen.
I typically do a full shutdown before booting into Windows. That acts just fine - I select windows and it starts up. I first know something is wrong because of how slow it starts up. Then, it attempts a Windows update, gets about 50%, and then blue screens.
The specific error message is: attempted write to readonly memory
I knew bootcamp wasn’t the best option, but dang it if I don’t want to lose hours of gameplay.
I see two options:

fix the blue screen and get back into windows OR
retrieve files without accessing the partition (Guessing this is not feasible. That’s probably like getting something out of a box without opening the box.)

But I’m not even sure where to start.
Actually your second choice is a bit odd but possibly the way to go.
macOS will certainly read (not write) from/to the default Windows 10 partition format, NTFS.
You should be able to access that partition and, assuming you know what to look for, copy the needed save files from your games to a flash drive to then transfer to your PC.
And depending on how &quot;hands on&quot; you are, you could theoretically remove the iMacs internal drive, stick it in an external USB enclosure and access the drive from your new Windows PC. Assuming it's not a fusion drive.
There are also utilities that will back up the Boot Camp partition, and presumably you might then be able to restore it to an external drive and access it from the new PC. That would depend on the software you use to do that and how it restores any backups it creates.
All of this depends on the Boot Camp partition being largely intact. you say nothing about that, just that it blue screens.
Also if you have a bootable Windows 10 flash drive (like the one Boot Camp created, you could boot from that and repair Windows. I use Windows 10 install media all the time to repair a blue screen error.
But there is absolutely no way to get the data off the partition without accessing it. As to get the data off of it (no matter how) you must access the partition.
Hopefully this gives you some starting points for avenues to recover your data.