External hard drive not appearing?

[Joel_Conison]

I was checking my scratch disc in PS preferences & noticed that my external hard drive which I use as my primary scratch disc is NOT showing up in the scratch disc preference section. I use one empty external hard drive as my #1 selection for scratch disc. #2, & #3 are other  external hard drives. I opened up the empty hard drive  to be sure it didn't crash & it did open. My question is : Why does it not appear in the scratch disc section while the other drives do appear?

Thanks

[Trevor.Dennis]

Hi Joel.  Are you using Mac or Windows?

[EDIT] I should have asked about Photoshop as well, in case you are using an old version.

[Joel_Conison]

Hi Trevor,     Sorry, I should have mentioned I am using a Mac. Also in the Scratch Discs portion of preferences there are only 3 disc listed. Two external drives & my system Mac drive.

Thanks for the help.

[Peru Bob]

If Windows, you may need to assign it a drive letter in Disk Management:

assign+it+a+drive+letter+in+Disk+Management

[Trevor.Dennis]

Bob I had the same thought, but that does not work for me.  Seven of the drives that show in Disk Management are external.  They are all formatted NTFS Basic, but only seven are available for Photoshop Scratch.  There does not appear to be any clues in the Status column either.   Google suggests that file format is the key with OSX, but I don't know how current that information is.

[gener7 · Accepted solution]

If you are going to assign a external scratch drive in Photoshop Mac, it must be formatted as Mac OS Extended (Journaled) or it will not show up in the Photoshop Scratch drive list, even if it is showing up in the Finder or Desktop. If it's already MacOS Extended, run Disk Utility First Aid on it.

Gene

[Joel_Conison]

Gene,

Thank you very much, that worked!

[Jon Urlie]

I'm having this same issue with my Transcend external disk.
As I was looking up how to format to Mac OS Extended, it looks like I need to erase the disc in the process.  Is there a way to format without erasing the data on the disc?

Jon 

[Test Screen Name]

No, formatting always wipes a disk. Don’t forget you need a backup!

[Stefano5E73]

Hi, I tried the suggestion above but my external drive still does not show up in the list of scratch disks.
I created a new partition and made sure it is MacOS Extended (Journaled), ran disk utility first aid on it and I still only see my internal HD listed. See attached screenshots.
Any help is welcome!

[Test Screen Name · Accepted solution]

One thing worth double checking is whether you can create a file on that partition. It might be that Photoshop hides read-only areas.

[Stefano5E73]

That worked!
I opened PS, saved a file to the new partition and now the drive magically appears in teh list of scratch disks. 
Didn't change any read-only settings, so it seems a bit of a UI bug to me, but thanks a lot, this solved it!

[DangersTeez]

I did the same thing still no show.

[Walter5E1F]

I have Photoshop on Windows 10.  My external hard drive does not appear in Scratch Disks. I tried uninstalling and reinstalling Photoshop.  No change.  I need to store on the external hard drive ("E" drive) because scratch disks are full on the internal hard drive.

[Glenn P Martin]

I had save a Photoshop file from within Photoshop onto the external drive first, then it appeared in the scratch disk list.