I've already looked around a bit and found only unrelated stuff.

My setup is a i7 2600k, 8gb ram, 250 gb SSD, 3* 500gb HD.

I first started installing on my SSD, but after 1.5 hours and 5% I stopped the installation and tried restarting it on my other drives. I first tried to drives named a: and b:, but those didn't work because blizzard apparently blocks the use of those. I tried my third HD (7 year old piece of junk) and I've gotten to 40% in 20 minutes.

Anybody know why a SSD with 500mb/s read and write is slower than an old HD? Or why A: and B: can't be used? The SSD works fine the rest of the time.

  • 3
    do you mean SSD - solid state drive? May 15, 2012 at 20:03
  • 4
    A:\B: may be disallowed because historically they are reserved for removable media. Try aliasing an unused drive letter to one of your HDD's, install there, and when done, you can copy/move the folder to your SSD.
    – Wikwocket
    May 15, 2012 at 20:10
  • Are you installing from disk or installing via download? if download; is it already fully downloaded and you are just executing the installation?
    – Frantumn
    May 15, 2012 at 20:12
  • About the drive. This may help you How can I change the installation directory to drive A?
    – Michel
    May 15, 2012 at 20:14
  • user1090190: Yes. Frantumn: Disk. Michel: Thanks, but already knew that. Was looking for the reason. @Wikwocket: Hmm. Kind of odd that something like that would prevent installation. But seems like a reasonable explanation.
    – SBoss
    May 15, 2012 at 21:11

1 Answer 1


According to this post on blizzard's forums, the installer prevents installing to a directory on the A: and B: drives.

You can't use the drive letters A or B with the installer as they're not allowed. (reserved for floppy drives)

You'll need to change the drive letter of the drive.

The exact error should be something like

The folder you selected cannot be used. Please select a different folder.

Luckily, there is an easy way to get around this issue.

  1. Close the installer
  2. Open a windows command prompt
  3. Enter the command subst Z: B:
  4. Open the installer and install to your Z: drive

Obviously, substitute Z: for any unmapped drive and B: for the drive that you would like to actually install on.

  • Sorry for the late marking as answer
    – SBoss
    Feb 22, 2013 at 15:54

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