Diane,
It is a commonly asked question in this forum. It means that in the best of all worlds, if you had two hard drives, you would be better off setting the scratch disk to a drive other than (usually) C.
The scratch disk is where photoshop creates a temporary file and relies on this area of a hard drive so that photoshop will perform well. When Photoshop closes, it deletes the temporary file and when it starts, it creates a new one.
Since photoshop relies heavily on this file you can get a lot of hard disk activity. If the file is on your C drive, it can, at some point "compete for time" with the Windows Temporary File (swapfile, pagefile, it goes by a couple of names).
So one is better off designating the Photoshop temp file to a different drive.
Couple of points. It is a courtesy message only, no harm will come from doing nothing. Second, if you don’t have a second hard drive you don’t have a choice. Third, you configure the scratch disk in Photoshop under Edit|Preferences|Plugins & Scratch Disks.
If you only have one drive, set it to C:\ instead of startup and the message goes away.
Final note. The performance gain is mostly theoretical except in the most extreme of circumstances. So again, no harm, just an "informational" message.
Peace,
Tony
Set the scratch disk to a drive that has plenty of free space on it. I have scratch files that get as large as 10 gig, but that’s rare for me. I put the scratch disk on a drive that has about 20 gig free space. If you don’t have that much free space, it’s no big deal, you tell photoshop what drive to use first, then when that runs out of space, what drive to ‘spill over’ onto.
