Is there anything I can do to possibly fix this problem or diagnose what's happening?
At 10:19am today I had the one I mentioned in agkernel.dll.
At 10:32am today I then had one in CameraRaw.dll
Looks like there are some related files that may be useful to see.
A DLL crashing could be because there are multiple copies and LR is finding the wrong one on the path.
Since you've had multiple crashes, it also could be that the catalog or Camera Raw cache or Previews cache are corrupted so it might not hurt to purge the Camera Raw cache, and create a new catalog with a new Previews folder then import everything from your old catalog into your new catalog (File / Import from another catalog) and see if things are better.
It could even be that the SSD, being flash memory, has a bad spot or two in critical areas.
Something is seriously wrong with your computer, either hardware, or software, or the catalog, itself.
You can roll back to previous versions of LR 2015.x by uninstalling LR, then downloading and installing the base .0 version, then installing the patch to whatever newer version you want, from here:
1) There's something wrong with the XMP file that's associated with this NEF.
2) There's a bug in LR.
Well, wouldn't you know... After I removed the XMP and redid all my edits, THEN tried the brush editing that was giving me fits, I havn't yet experienced a crash. Is it possible that the XMP file was somehow corrupt? Any way to tell other than just deleting it?
I don't think I'm completely out of the woods yet, after all I've only been using it again for a few minutes. But it was so bad before, it was unbearable. I'm hoping that I don't see he agkernel.dll crash anymore now that I moved my catalog and reinstalled LR.
Phew, sorry for so much typing. But maybe it'll help somebody else. :)
The XMP file is only a copy of what’s in the LR database, already. When you say you imported your entire catalog, did you import FROM the catalog FILE or did you import all the photos, again, using whatever settings were stored in the XMPs?
The XMP file could have been in a bad spot on your storage device that holds your photos and deleting it let LR recreate it in a different location but that would leave the bad spot free for another file to be written there.