I have read some posts about this, but many revolve around not having URL rewrite working properly.
I am using pagecache using the disk (enhanced) method, which I believe uses URL rewrite and that's working fine. Also, in my compatibility report it says ENABLED next to URL rewrite.
So I'm stumped as to why minify is failing. I DO still get the "It appears Minify URL rewriting is not working." error (technical error received 500 instead of OK).
I have also tried using minify in xcache mode, the error goes, but I still get internal server errors (500) for the minified files.
I feel like the lack of information about this that I've found means that it is either a stupid error I'm making, or a rare server setup causing the issue, either way any help is appreciated.
P.S am running in manual mode specifying files to minify. Tried using help wizard but it just had the ajax spinner going for ages so entered it manually, all URI's verified.