AutoCAD just crashed and it doesnt seem to have actually saved when I pressed save all day. It has taken me to drawing recovery manager and given me a file from 9:38 which is a .sv$ file. The auto save says it creates a .ac$ file every 5mins but I cant find and file with a suitable file name

Can anyone help?

Have you tried turning your machine off and then on again?

Try manually changing the file extension from .ac$ to .dwg (save a copy first)

Edit: to find the files go to
Tools > Options > Files
“Automatic Save File Location” to see where they are

You might need ‘show hidden files’ checked, too

Is there a *.bak file available?

Copy and rename it as *.dwg and try opening…

http://www.cad-addict.com/2009/07/autocad-use-autosave-files-to-recover.html

I have had to restart
I can’t find any files named .ac$ even though autosave apparently creates them, I can only find .sv$ and .bak both of which are very old (ie this morning or yesterday

Cougar, you are a legend

It’s in a hidden folder. You need to go to view, file types and uncheck or check show hidden files and folders.
I’m not on a pc atm, so the instructions will be similar to above.