Error 1625
This installation is forbidden by system policy. Contact your system administrator.
A Windows policy is blocking the installation. On a managed work computer that is deliberate. On a personal machine it is usually a leftover policy setting.
What it actually means
Group Policy can disable Windows Installer entirely or restrict it to elevated installs. The setting survives whatever configured it, so a machine that was once managed, or that had a security tool installed, can keep enforcing the restriction long afterwards.
How to fix it, in order
Ordered by how often each one is the answer, not by how clever it sounds.
- 01On a work computer, stop here and ask IT. The restriction is intentional and bypassing it is likely to breach policy.
- 02On a personal machine, check the policy: press Windows and R, type gpedit.msc, and go to Computer Configuration, Administrative Templates, Windows Components, Windows Installer.
- 03Look at "Turn off Windows Installer" and set it to Not Configured or Disabled.
- 04On Windows Home, gpedit is absent. Check the registry instead: under HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\Installer, a DisableMSI value set to 1 or 2 is the cause.
- 05Restart after changing it, since policy is read at startup.
Common questions
- What does "installation is forbidden by system policy" mean?
- Group Policy has disabled Windows Installer. On a managed computer this is intentional and IT should be asked. On a personal machine, check the Windows Installer policy in gpedit.msc, or the DisableMSI registry value on Windows Home.
Before you retry the installer
If the package came from anywhere other than the publisher, confirm it is the file they actually shipped. Check its SHA-256 against our index, which settles in seconds whether you are debugging an installer or a damaged download.