So I've recently 'upgraded' to Windows 10 from 7, and lately my FFXI game crashes within the first 5 minutes of me being logged in. I keep getting this error:

pol.exe has stopped working
A problem caused the program to stop working correctly. Windows will close the program and notify you if a solution is available.

I tried updating Nasomi using http://nasomi.com/forum/viewtopic.php?f=7&t=40 but it didn't fix the problem. Please help. Totally unplayable.

Have you tried compatibility mode? Try right click on all related exe (pol, ashita), go to properties, should be somewhere in there. I'm sorry I don't have Win 10 installed to be more precise.

I've got a Win 10 from 7 setup and haven't had that issue. May want to look into updating the VC and DX8 files either by forcing an update or deleting and reinstalling. I mean, compatability(right click files -> properties it's on of the tabs) wouldn't hurt any but it shouldn't be needed. Also maybe try forcing an FFXI update. Delete your VTABLE.DAT from the FFXI main folder and then run the POL like in the original install directions.

There's a thread around here with the steps laid out but this is the shorthand.
PS-Nasomi just posted updated install packages so you could wipe and install or maybe just "repair" over what you have.