An increasingly common problem on Microsoft Windows computers is the corrupted user profile error. Everything seems fine until you attempt to log on. Then the error strikes. Your user profile is corrupted and you cannot log on any longer. (error: "User Profile Service failed the logon, user profile cannot be loaded") This is an interesting problem, because how can you fix an error without being able to log on to your PC?

Fortunately, there are a variety of solutions at one's disposal, but unfortunately none  are very simple. Below we will explore three potential resolutions that will work for users that have their data backed up and are simply looking to re-gain access to their user accounts. But first let's talk about what a user profile is so that we know what we're trying to repair!

The Windows user profile is essentially your account's configuration data. It contains critical information for Windows to determine how your account is configured, such as the way your libraries (Documents, Pictures, Music, etc) are configured, your NTUSER data (personal settings, software locations), cookies from your web browsing, temporary as well as cache files and more. The user profile dates back to the days of Windows 95 when user accounts were given unique configurations to allow multiple users easier access to their own files and settings. Without the user profile functioning properly one would not be able to user their computer properly without having to reconfigure parts of their user account from scratch.

Remember that these solutions are somewhat advanced. If you have any reservations about performing them you can always hire a professional to help you instead.

1. Run a Check Disk

Run a check disk to see if the corruption is due to a bad file system. If you can boot in to the recovery console, which is installed on most Windows Vista and Windows 7 computers you will be able to access the command prompt. Most systems allow access to the recovery console by hitting F8 before the Windows screen appears. When you are in the recovery console you'll want to select advanced repair options and choose command prompt. From the command prompt you need to determine which drive hosts your operating system. For example if you issue the command:

dir C:

The command will return a list of directories including a Windows directory, then chances are your OS is also on the C: drive. If not you can run the same command to check drives D: or E:.

Now you want to run a full chkdsk to examine the disk for any bad file system data.

WARNING: if your data is not backed up this command can result in data loss. DO NOT run a chkdsk if your data is not backed up. In fact if your data is not backed up you shouldn't perform any troubleshooting until it is.

chkdsk /r /f /x C:

(The parameters shown above perform different functions: /r - locates bad sectors, /f fixes the errors in the volume, /x - forces the volume to dismount, if necessary.)

Once chkdsk finishes (it may take several hours) the final log will tell you if there were any errors corrected. If so, then perhaps the issue is resolved.

2. Run a System Restore

Run a system restore to repair damaged system files. If the chkdsk does not help, you can re-visit the recovery console and attempt to run a system restore. These restores are non-destructive and should not overwrite personal data, but if your data is not backed up please do not proceed. A damaged hard drive may fail during a system restore.

Try to choose a date that pre-dates whenever the system profile corruption began, but not too far back as the further back one goes, the less likely a restore will be successful.

Wait for the process to complete, it may take quite a while. Once it completes please reboot and see if you can log in.

3. Log in With Another Account

Log in with another account that works, you may be able to use a Hotfix. If you have another user account that can log on, but yours can't then a special Microsoft Windows hotfix may help.

Download the hotfix in the link (above). Run it and follow the instructions. Once completed try to reboot and see if the account is usable again.

If none of these methods resolve the corrupted user profile on your Microsoft Windows computer or your data is not backed up, you should consider hiring a professional to examine the misbehaving computer.