QuickBooks Error 1327: Invalid Drive Letter During Install

Last reviewed 2026-09-11 4 min read

Error 1327 stops a QuickBooks Desktop install or update because Windows points setup at a drive that no longer exists; here is how to get setup finished.

Error 1327 appears when you install or update QuickBooks Desktop and Windows reports a drive that does not exist. The installer stops before it writes a single file. The letter in the message is the clue, and in our experience the cause is almost always a mapping or a folder location left behind by earlier software.

The message on screen

QuickBooks surfaces the Windows Installer message almost word for word:

Error 1327. Invalid Drive: E:\

The letter varies. It might be F:, G:, or any letter that is not in use on the machine in front of you. During an update, the dialog can appear midway through patching, minutes after the process started. Dismissing the message rolls the install back.

The meaning behind the code

The 1327 code belongs to Windows Installer, not to QuickBooks itself. Before writing files, the MSI engine checks every path it plans to use: the Windows temp folder, the destination folder, and the per-user folders recorded in your profile. If any of those paths begins with a drive letter Windows cannot resolve, the engine halts and reports 1327. QuickBooks is simply the messenger.

Common triggers

Three situations cover nearly every 1327 case we handle.

A mapped network drive. If an earlier program was installed from, or pointed at, a mapped share, the letter stays recorded in your profile. When the server or NAS goes offline, the letter points nowhere.

A removed or re-lettered USB drive. External drives often change letters between sessions. A path recorded as G: last month may now belong to nothing.

Shell folders on a missing drive. If Documents, AppData, or the temp folder was redirected to a second drive that has since been removed, every MSI-based install on that machine inherits the broken path.

How do you fix error 1327?

Work through the scenarios in order. Each one ends with rerunning the QuickBooks installer, so stop as soon as setup completes.

Clear a stale mapped drive. Open a Command Prompt and type net use. Any mapping marked Unavailable, or any letter matching the one in the error, is your suspect. Remove it with net use E: /delete, substituting the letter from your message, then rerun the installer.
Plug the drive back in. If the letter belongs to a USB drive you still use, reconnect it, or restore its old letter in Disk Management, and run setup again. Change the letter back once QuickBooks is installed.
Create the missing letter temporarily. When the drive is gone for good but the installer still demands it, let a local folder stand in for it. In a Command Prompt:
```
mkdir C:\temp_drive
subst E: C:\temp_drive
```
Run the QuickBooks install again. When it finishes, release the letter with subst E: /d.
Repair shell folders that point at the missing drive. If steps 1 to 3 do not clear the error, your user profile is probably still aimed at the dead letter. Check the TEMP and TMP variables first, under Environment Variables in System Properties, and set both to %USERPROFILE%\AppData\Local\Temp. If that is not the culprit, open Registry Editor and look under HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders. Any entry beginning with the missing letter should point to the equivalent path on C: instead. Export the key before changing anything.
Try a different Windows account. A second administrator account carries its own, usually clean, profile paths. Installing from that account bypasses the broken reference, and you can tidy the first profile afterwards.

After any of these changes, restart the machine and run the installer by right-clicking it and choosing Run as administrator.

Keeping it from coming back

Install QuickBooks from a local path. Copy the installer to the desktop rather than running it straight from a network share.

Keep drive letters stable. In Disk Management you can assign a permanent letter to each external drive, so a re-lettered device cannot break a recorded path.

Leave Documents and temp folders on C:. Redirecting them to a second drive saves space, but it ties every future install to that drive surviving.

When a drive retires, remove its mappings and profile references that same week, not the next time an update falls due. That habit alone prevents most of the repeat 1327 calls we field.