Fix ERROR_FAIL_NOACTION_REBOOT (0X0000015E) – Quick Reboot Fix

Quick answer

Restart your computer. That's it. If you still see the error after a reboot, you've got a stuck pending-reboot flag that needs clearing manually.

What's going on here

This error code—0X0000015E—shows up when Windows or an installer tries to do something (install a driver, update, or application) and finds that a reboot is already pending. Think of it as a lock. The system says "I need to finish the last reboot before I can start a new operation." You'll see this most often after a failed Windows update, a driver install that didn't finish, or when you cancel a restart mid-way. The real fix is simple: do the reboot that's been waiting. But sometimes the flag doesn't clear, and you have to hunt it down.

How to fix it – main steps

Restart your PC normally. Click Start > Power > Restart. After the reboot, the error should be gone. Check by trying whatever install or update you were doing before.
If the error returns, check for a stuck pending-reboot flag. Open Registry Editor (press Windows Key + R, type regedit, hit Enter). Go to this key:
```
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager
```
Look in the right pane for a value named PendingFileRenameOperations. If it's there and has data in it, that's your culprit. Right-click it and choose Delete. Confirm. Then restart again.
If that doesn't fix it, check the Windows Update pending reboot flag. Open Command Prompt as Administrator (right-click Start, choose Command Prompt (Admin) or Terminal (Admin)). Run this command:
```
reg query "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v RebootRequired
```
If it returns RebootRequired with a value of 1, delete that value with:
```
reg delete "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Auto Update" /v RebootRequired /f
```
Then restart.
Still stuck? Use a tool. Download Microsoft's PendingRebootChecker (part of the Microsoft Deployment Toolkit) or use a free utility like PendMoves from Sysinternals. Run PendMoves.exe from an admin command prompt. It will show any pending file rename operations. If you see entries, you can clear them with:
```
pendmoves -c
```
Then reboot.

Alternative fixes if the main steps fail

Check the Windows Installer service. Sometimes the MSI installer caches a reboot requirement. Open Services (services.msc), find Windows Installer, right-click and Restart it. Then try your install again.
Look for hidden pending updates. Open Settings > Update & Security > Windows Update. Click "Check for updates". If any updates are stuck, click "Restart now" from that page. Let it finish fully.
Use the Windows Update Troubleshooter. Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update. Run it. It often clears stuck reboot flags.
If all else fails, boot into Safe Mode. Restart, hold Shift while clicking Restart, then go to Troubleshoot > Advanced Options > Startup Settings > Restart. Choose Safe Mode (4). In Safe Mode, run the registry steps again. The flag is more likely to clear here.

How to prevent this from happening again

Always let updates and installs finish their reboot. If you see "Restart required," do it right then—don't put it off. That pending flag is fragile and can get corrupted if you interrupt it.
Don't cancel a restart mid-boot. If Windows is applying updates at shutdown, let it finish. Force-powering off during that phase is the #1 cause of stuck reboot flags.
Use the built-in reboot instead of Shut Down. On Windows 10 and 11, Shut Down uses Fast Startup, which sometimes doesn't clear all pending operations. Restart always does a full reboot and clears the flag. So if you see that error, always choose Restart, not Shut Down.

Pro tip from the help desk: If you're a sysadmin managing multiple machines, you can check for pending reboots remotely using PowerShell: Get-CimInstance -ClassName Win32_ReliabilityRecords -Filter "Logfile = 'System' AND Message like '%reboot%'". But for a single workstation, just restart and be done with it.

That's it. This error is one of the easier ones to fix. Nine times out of ten, a single restart does the job. When it doesn't, the registry key or PendMoves tool will finish the cleanup. Don't overthink it.