The “This installation is forbidden by system policy” message is, honestly, one of those errors that makes you want to tear your hair out. Basically, Windows is stopping you from installing certain programs because it thinks there’s a policy blocking it. Sometimes, it’s because a Windows update changed some registry or group policy settings, or maybe some third-party security tool decided to lock things down. Happens more often than you’d want, especially on work machines or if someone else manages your PC. It’s annoying, but not impossible to fix—if you know where to look, that is. This guide walks through a bunch of practical things to try, from quick resets to digging into registry files. Once fixed, you should be able to install that app or program like normal. Expect some of these to require admin rights or admin-level tweaking, so be ready to punch in your password or get permission from your tech admin if needed.
How to Fix “This Installation is Forbidden by System Policy” in Windows 11
Use Command Prompt to Re-register Windows Installer
This is kind of the nuclear option, but it works surprisingly often. If the installer service is corrupted or misregistered, Windows throws this error. Re-registering can clear that up.
- Open Command Prompt as administrator—hit Windows key + S, type
cmd, then right-click and select Run as administrator. - Type these commands one after the other. Hit Enter after each:
%windir%\system32\msiexec.exe /unregister%windir%\system32\msiexec.exe /regserver%windir%\syswow64\msiexec.exe /unregister%windir%\syswow64\msiexec.exe /regserver
After running those, restart your PC. Sometimes, this fixes the policy issues affecting installers without needing to dive into registry edits. On some setups, this feels super hit-or-miss, but it’s worth a shot before more invasive tweaks.
Check and Enable Windows Installer Service
If that service is disabled or stuck in the wrong startup mode, Windows might block installs with this message. It’s kind of weird that Windows doesn’t auto-start the service every time, but here we are.
- Press Windows key + R, type
services.msc, and hit Enter. - Find Windows Installer in the list. Double-click it to open properties.
- In the Startup type, choose Manual. If it’s disabled, click Start to enable it.
- Hit Apply and then OK.
This should make sure Windows allows installer processes to run. Sometimes, it’s a simple fix—other times, a lingering service issue causes the block.
Modify Local Group Policy (if available)
This is the big guns — if your Windows version has Group Policy Editor, you can tweak settings that might be stopping installation. It’s often the cause if the policy was altered by a previous admin or malware.
- Press Windows + R, type
gpedit.msc, and hit Enter. - Navigate to Computer Configuration > Administrative Templates > Windows Components > Windows Installer.
- Look for Prohibit non-administrators from applying vendor signed updates, or similar policies.
- Double-click, set it to Disabled or Not Configured.
- Click Apply and OK.
This usually lifts restrictions on install attempts for non-admins and might resolve the error. Just be warned—if these settings are missing, it might mean your Windows version doesn’t have Group Policy Editor, or you’re on Windows Home.
Disable User Account Control (UAC) Temporarily
Gear a little cautious here, but turning UAC off can sometimes bypass what Windows thinks are security policies. Not a recommended long-term fix, but if you’re desperate and trust the source of the installer, it’s worth a try.
- Search for Change User Account Control Settings.
- Move the slider down to Never Notify.
- Click OK, then confirm with Yes when UAC prompts.
Now, try running the installer again. If it works, probably some UAC policy was blocking the process. Remember to turn UAC back on after you’re done—because of course, Windows has to make it harder than necessary.
Edit the System Registry (a bit more advanced)
If none of the above worked, fighting this error sometimes means hacking into the registry. Be super careful—mistakes here can cause other issues. Only do this if you’re comfortable changing system settings.
- Press Windows + R, type
regedit, and hit Enter. - Navigate to:
HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows. - Right-click on Windows, choose New > Key.
- Name the new key Installer, then hit Enter.
- With Installer selected, right-click on the right side, choose New > DWORD (32-bit) Value.
- Name it DisableLUAPatching.
- Double-click it, set Value Data to 1, then hit OK.
Close the registry editor and reboot. Now Windows should be less strict with policies blocking installer installations. Note: Modifying this can have side effects, so only do it if you’re confident, and maybe back up the registry first.
Final Option: Re-Register Windows Installer
Nope, this isn’t just about re-installing the app — it’s about re-registering the installer service itself. If everything else fails, this often clears corrupt configurations.
- Open Command Prompt as admin (hit Windows key + S, search
cmd, right-click, Run as Administrator). - Run these commands exactly as shown:
%windir%\system32\msiexec.exe /unregister%windir%\system32\msiexec.exe /regserver%windir%\syswow64\msiexec.exe /unregister%windir%\syswow64\msiexec.exe /regserver
Then, restart your PC. Sometimes, this resets whatever policy or registry lock was confusing Windows enough to block your install. It’s a tried-and-true method for stubborn issues.
Summary
- Run commands to reset and re-register installer services.
- Check that the Windows Installer service is enabled and set to manual.
- Adjust Local Group Policy if available.
- Temporarily disable UAC, but turn it back on afterwards.
- If feeling brave, tweak the registry—just be careful.
- Finally, try re-registering the installer service for good measure.
Wrap-up
This mess can be irritating, especially if you’re just trying to install something quick. In most cases, re-registering the installer or enabling the service does the trick. Sometimes it’s a policy setting lurking somewhere, or a registry tweak that got set wrong. Good to remember: some issues hang around because of weird permissions or leftover security policies, so thorough checking is key.
Hopefully, this shaves off a few hours for someone. Just remember — don’t go messing with the registry unless you’re comfortable, and always backup before making big changes. Good luck, and happy installing!