You sign into Windows 11 as normal.

Your password or PIN works, but something immediately looks wrong.

Your desktop has changed. Your wallpaper has disappeared. Your usual shortcuts are missing. Outlook, OneDrive or other applications seem to have forgotten their settings.

Then Windows displays a message such as:

“We can’t sign in to your account.”

or:

“You’ve been signed in with a temporary profile.”

It can look as though Windows has deleted your account.

Usually, it hasn't.

Windows has failed to load your normal user profile and has instead signed you into a temporary profile so that you can still access the computer.

Your original files may still be sitting safely under your normal folder in:

C:\Users\YourName

The priority is to recover the proper profile without accidentally losing new work or damaging the profile configuration further.

Important: Don't Save Important Work in the Temporary Profile

This is the first thing you should know.

Microsoft explicitly warns that files created or changed while you are signed into a temporary profile can be lost when you sign out.

If you have already created something important during the temporary session, save a copy somewhere safe before doing anything else.

For example:

• external USB storage
• an appropriate network location
• confirmed cloud storage
• another known-safe location outside the temporary profile

Do not spend the whole day working from the temporary desktop assuming Windows will keep everything.

How Do I Know I'm Using a Temporary Profile?

Common symptoms include:

• unfamiliar desktop
• missing desktop shortcuts
• default wallpaper
• applications behaving as though they have just been installed
• missing application preferences
• Windows displaying a temporary-profile notification
• files apparently disappearing from Desktop or Documents

You may also find yourself working under a folder such as:

C:\Users\TEMP

rather than your normal profile.

Before assuming your files have disappeared, open:

C:\Users

Look for your original username.

For example:

C:\Users\Carl

Open the folder and check:

• Desktop
• Documents
• Pictures
• Downloads

If your data is still there, that is encouraging.

Do not start moving everything into the temporary profile.

Why Does Windows Create a Temporary Profile?

Windows needs to load a user profile every time you sign in.

That profile contains far more than your Documents folder.

It includes information about:

• desktop configuration
• application settings
• user Registry settings
• OneDrive configuration
• Start menu preferences
• Windows settings
• application data

If Windows cannot load that profile correctly, it may create a temporary environment instead.

Possible causes include:

• an interrupted Windows update
• profile corruption
• unexpected shutdown
• low disk space
• storage problems
• damaged permissions
• security software interfering with sign-in
• damaged Registry profile information

The important thing is not to assume immediately that the .bak Registry problem is definitely responsible.

Start with Microsoft's safer recovery steps first.

Step 1: Restart the PC

A temporary profile can sometimes be caused by a transient Windows problem.

Restart the computer.

Do not simply sign out and back in repeatedly.

Use:

Start > Power > Restart

Then sign into your normal account again.

Microsoft specifically notes that it can take more than one restart before the normal profile loads successfully.

If everything returns—desktop, files and settings—you may not need to do anything else.

If Windows creates another temporary profile, continue.

Step 2: Try Safe Mode Before Editing the Registry

Microsoft's current guidance recommends restarting into Safe Mode and attempting to sign into the original profile.

From the Windows sign-in screen:

1. Hold Shift.
2. Select Power > Restart.
3. Choose Troubleshoot.
4. Select Advanced options.
5. Select Startup Settings.
6. Select Restart.
7. Choose Safe Mode or Safe Mode with Networking.

One important difference: Microsoft notes that PIN and biometric sign-in aren't available in Safe Mode, so you will need the account password.

Sign into the original account.

Then restart Windows normally and try again.

If the normal profile loads, stop there.

There is no reason to modify the Registry if the problem has already been resolved.

Step 3: Check Free Disk Space

Before attempting a more advanced repair, check the system drive.

Open:

File Explorer > This PC

Look at the free space on C:.

A system drive with virtually no available space can cause all sorts of Windows problems.

If storage is critically low, safely remove unnecessary data or move appropriate files elsewhere before continuing.

Do not install random “PC cleaner” software to solve the problem.

Use Windows Storage settings and remove files you understand.

Step 4: Check That Your Original Profile Still Exists

Open:

C:\Users

Look for your original profile folder.

For example:

C:\Users\Carl

If it exists, inspect it.

Do you see your normal:

• Desktop
• Documents
• Pictures
• Downloads

If the answer is yes, back up important information before proceeding with advanced repairs.

This is particularly important before changing Registry profile mappings.

Step 5: Check Which Account Windows Thinks You're Using

Before editing anything, it can be useful to identify the Windows security identifier—or SID—associated with the account.

Open Command Prompt and run:

whoami /user

Windows displays the current SID.

It looks something like:

S-1-5-21-xxxxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-1001

The exact numbers will be different on every machine.

SIDs matter because Windows stores profile configuration against them rather than simply using the visible account name.

Step 6: Inspect ProfileList

Now we reach the Registry repair.

This is an advanced troubleshooting step.

Press:

Windows key + R

Enter:

regedit

Then navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList

Under ProfileList you will see several keys beginning with:

S-1-5-...

These represent Windows security identifiers.

Do not start deleting them.

Look at ProfileImagePath

Select each relevant long SID and look at:

ProfileImagePath

This tells you which profile folder that SID points to.

For example:

C:\Users\Carl

or:

C:\Users\TEMP

This is much more useful than guessing based purely on the SID name.

Recent Microsoft Q&A troubleshooting continues to use ProfileImagePath to distinguish the real account from a temporary profile when investigating the .bak condition.

Step 7: Look for the .bak Pattern

A classic temporary-profile failure can produce two very similar SID entries.

For example:

S-1-5-21-xxxxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-1001

and:

S-1-5-21-xxxxxxxxxx-xxxxxxxxxx-xxxxxxxxxx-1001.bak

The .bak entry may point to the original profile.

The non-.bak entry may point to the temporary profile.

But do not assume that is true.

Check ProfileImagePath first.

That is one of the most important safeguards in this entire procedure.

Step 8: Back Up the Registry Entry Before Changing It

Before modifying ProfileList, export the relevant key.

In Registry Editor:

1. Right-click the relevant key.
2. Choose Export.
3. Save the .reg file somewhere safe.

This gives you a record of the original configuration.

Also make sure your important user files have been backed up.

You are modifying the configuration Windows uses to associate an account with its user profile.

This is not something to change casually.

Step 9: Repair the .bak Profile Mapping

Only proceed if you have positively identified:

• the SID associated with the real user
• the original profile folder
• the temporary profile
• the corresponding .bak entry

A common repair pattern is to rename the temporary SID entry so it is out of the way, then remove .bak from the SID pointing to the genuine user profile.

Microsoft Q&A guidance continues to describe this repair for the classic duplicate-SID .bak scenario.

For example, you might temporarily rename:

...-1001

to:

...-1001.old

Then rename:

...-1001.bak

to:

...-1001

The exact entries depend on what ProfileImagePath shows.

Do not blindly copy SID names from an online example.

Your identifiers will be different.

What About State and RefCount?

Some versions of this repair also involve checking values named:

State

and:

RefCount

where present.

These may be reset to 0 as part of repairing a stuck profile state.

However, Registry layouts and the underlying cause can differ.

If you don't understand what the entries represent, stop rather than experimenting.

For a company PC, this is a sensible point to involve IT support.

Step 10: Restart Windows

Once the profile mapping has been corrected:

Restart the PC.

Sign into the original account.

Check whether your:

• desktop
• files
• application settings
• OneDrive configuration
• normal Windows environment

have returned.

If they have, do not immediately delete old Registry entries or folders.

First confirm that the computer remains stable after another restart and that the user's data is intact.

What If the .bak Fix Doesn't Work?

Do not keep repeatedly renaming Registry keys.

If Windows continues creating temporary profiles, the underlying user profile may genuinely be corrupted.

Microsoft's supported escalation is to create a new local administrator account and migrate the user's personal data from the damaged profile into the new one.

This can be safer than continually trying to revive a badly damaged profile.

Don't Copy the Entire Old Profile

If you create a replacement account, be selective.

Copy actual user data such as:

• Documents
• Desktop files
• Pictures
• appropriate Downloads
• other known business data

Do not blindly copy the entire old profile over the new one.

That risks bringing damaged configuration into the replacement profile.

In particular, avoid casually copying profile Registry files such as:

NTUSER.DAT

A new profile should remain a new profile.

Move the data you need and recreate application configuration properly.

Check OneDrive Before Copying Huge Amounts of Data

Business users frequently have Desktop and Documents redirected or synchronised through OneDrive.

Before copying hundreds of gigabytes manually, establish:

• what exists locally
• what exists in OneDrive
• whether OneDrive was using Files On-Demand
• whether Desktop/Documents backup was enabled

Otherwise, you can create duplicate files or unnecessarily download huge cloud libraries.

What If the Temporary Profile Keeps Coming Back?

This is the point where the problem becomes more interesting.

If you repair the .bak entry and everything works for two days, then Windows creates another temporary profile, the Registry entry is probably a symptom rather than the root cause.

Investigate why the profile keeps failing.

Potential areas include:

• insufficient disk space
• SSD problems
• file-system errors
• damaged profile permissions
• endpoint-security software
• Windows corruption
• repeated hard shutdowns
• profile-management software
• domain or Group Policy issues

A January 2026 Microsoft Q&A case illustrates exactly this situation: removing .bak fixed the profile temporarily, but the error returned, prompting investigation of storage and profile corruption rather than simply repeating the Registry edit.

Check Event Viewer

For recurring problems, Event Viewer can provide considerably more information than repeatedly editing ProfileList.

Open:

Event Viewer

Then investigate:

Applications and Services Logs > Microsoft > Windows > User Profile Service

Look for errors around the time the failed sign-in occurred.

The event details can help reveal whether Windows was unable to:

• access a profile file
• load the user Registry hive
• obtain permissions
• release the profile correctly
• access storage

For a business environment, this evidence is particularly useful because it helps distinguish a one-off corrupted profile from a wider infrastructure problem.

Don't Disable Business Security Software Blindly

Microsoft's temporary-profile troubleshooting documentation includes security software among the possible things to investigate when a profile repeatedly fails to load.

That does not mean employees should randomly disable Microsoft Defender or third-party endpoint protection.

On a managed business computer, security software may provide:

• malware protection
• ransomware protection
• web filtering
• compliance
• endpoint detection and response
• remote monitoring

If security software appears involved, investigate it through the appropriate management platform or IT provider.

Temporary Profile vs Corrupted Profile

These terms are related but not identical.

A temporary profile is the environment Windows gives you because it could not load the expected profile.

A corrupted profile may be the underlying reason Windows could not load it.

Sometimes restarting solves the temporary condition.

Sometimes correcting the Registry association solves it.

Sometimes the original profile itself is sufficiently damaged that creating a clean replacement is the better option.

That is why the Registry fix should not automatically be step one.

The Safe Troubleshooting Order

For most Windows 11 temporary-profile problems, I would use this sequence:

1. Save anything created in the temporary profile somewhere safe.
2. Restart Windows.
3. Try another normal restart if necessary.
4. Use Safe Mode and sign into the original account.
5. Restart normally.
6. Check available disk space.
7. Confirm the original profile exists under C:\Users.
8. Back up important data.
9. Inspect ProfileList and ProfileImagePath.
10. Apply the .bak Registry repair only if the evidence matches that specific problem.
11. Restart and verify the profile.
12. If it fails again, investigate the underlying cause.
13. Create a clean replacement profile if the original is genuinely corrupted.

That approach is safer than immediately deleting Registry keys because a YouTube video said .bak means “delete this”.

How Hamilton Group Can Help

A temporary profile is particularly disruptive on a business PC because the employee may suddenly appear to have lost access to their normal desktop, Microsoft 365 configuration, OneDrive, application settings and business files.

Hamilton Group can help with:

• Windows 11 profile problems
• temporary profile errors
• Windows Registry troubleshooting
• corrupted Windows profiles
• OneDrive
• Microsoft 365
• Microsoft Intune
• Windows Update problems
• storage diagnostics
• business data recovery
• Windows device management

The priority should be to protect the user's data first, restore the normal working environment second, and then understand why the profile failed so the problem does not simply return.

Visit or call 0330 043 0069 to discuss Windows 11 and business IT support.