Please see my earlier post here. Microsoft has identified one cause of an endless reboot occurring after an attempt to upgrade a computer from Windows Vista to Windows 7. Another upgrader has found another cause for the reboot loop.

MS found that folders in the My Documents folder with a path length that is too long can cause the problem. I’ll reproduce the steps posted by Microsoft forum moderator Kevin Hau below (I’ve edited them for spelling, grammar, and clarity). Please read the instructions over before attempting them. (The original post is here – use the Find feature of your browser to locate the string “Friday, November 13, 2009 2:41 AM” (without quotes)).

The other cause, discovered by Jerry Ham, is if the default location for My Documents has been redirected. This page shows how to change it back.

If either of these solutions work for you, please go to the forum where the posts are displayed and post a reply stating that the fix worked. It’s important that Microsoft knows what works so that they can focus efforts on finding a procedure for users who have not succeeded in correcting their problem.

Hello,

We have identified a resolution for some of these reboot loops. Please see the steps below for details:

We will start by booting into Windows Recovery Environment using the same steps above. I will list them again here for completion’s sake:

1. Boot using the Windows 7 installation DVD
2. Choose your language settings and hit “Next”
3. Click on “Repair Your Computer” link at the bottom of the screen. This will launch Windows RE [Windows Recovery Environment].

NOTE: Do not click on “Install Now”

4. Choose the OS to repair, and take note of the Drive Letter assigned to the operating System.
5. You should see “Windows 7” and D: (the drive letter may be different)
6. Click Next and you should see a list of the recovery tools
7. Click on “Command Prompt”
8. You will see “X:Sources>” in white on a black background – you can type commands here

Now please follow the steps below:

1. Type “cd c:users” at the command prompt [and press Enter]. [After X:Sources>, type cd c:users. It should look like this before you press Enter: X:Sources>cd c:users ]
2. Type “dir /s /p”, [press Enter], and look for the words “is too long”. [If you see this, write down the path of the folder.]
3. If you don’t see “is too long” on the first page, press a key to get the next page
4. Look on the second page for “is too long”.
5. Continue to press a key to advance in pages until you find all the strings “is too long”. (This may take quite a few pages to get to the end)

NOTE: You may see more than 1 entry that has “is too long”, please take a note of each entry as we will need the folder names in later steps [meaning write down the path of the folder for every is too long entry].

Once you have identified all the folders with “is too long” we will need to move them into a temp location.

7. Type “move” followed by the path of the folder, [then a space], then the name of the temporary location to move to, [then press Enter]:

EXAMPLE: MOVE C:USERSBOBDOCUMENTSDOCUMENTS C:TEMP
[If the path contains a space, enclose the path in quotes.]
[EXAMPLE: MOVE “C:USERSBOB’SDOCUMENTSBOB’S DOCUMENTS” C:TEMP]

8. Once all the invalid folders have been moved, repeat steps 1 and 2 to verify that there are no other folders with “is too long”
9. Once completed, restart the computer and you should be able to successfully boot into Vista.

10. Once back into a working Vista, open “Computer” and navigate to C:Users and open your username folder.
11. Right click on each folder one by one and choose “Properties”.
12. Click on the Location tab and confirm that the path shown is correctly displaying the path for this folder.

Example: The properties / location of C:UsersBOBDocuments should have the same correct path listed on the location tab: “C:UsersBOBDocuments”.

13. If any folder’s location is not correct, click on “Restore Defaults” and repeat
14. Once all the folders have been corrected, please reboot the computer and try the upgrade process again.

I have unlocked this thread, please let me know if you see success with the above steps.