Error 1601 and 1719: Windows Installer Service Could Not Be Accessed

What causes Error 1601 and 1719

• The service is not enabled. Microsoft's services guidance lists Windows Installer (msiserver) with startup type Manual and says that if it is disabled, any service that explicitly depends on it becomes unable to start.
• The service is not properly registered: it is the second condition Microsoft's message names.

How to fix Error 1601 and 1719, safest step first

Microsoft's message asks for two things to be verified: that the service is enabled and that it is registered. Start with the read-only checks below, then go in this order.

1. 01

   Make a restore point before the steps that change something

   Select Start, type Create a restore point, open it, and on the System Protection tab choose Create. Microsoft notes that System Protection is not turned on by default; if Create is greyed out, choose Configure and turn it on for the system drive first.

   To undo: A restore point changes nothing by itself. To go back later, run System Restore and pick it: Microsoft says it reverts system files, the registry and installed programs, and leaves your personal files alone.

2. 02

   If the service is Disabled, put it back to Manual

   Run the first check below. If START_TYPE says DISABLED, open Command Prompt as administrator and run sc.exe config msiserver start= demand (the space after start= is required). Manual is the startup type Microsoft documents for this service.

   To undo: sc.exe config msiserver start= disabled puts back the state you found. On a work PC a policy may have disabled it on purpose: ask the administrator first.

3. 03

   Restart the PC and try once more

   Use Start > Power > Restart. It is the first solution on Microsoft's page for programs that will not install or uninstall.

   To undo: Nothing to undo: a restart changes no setting.

4. 04

   On Windows 10, run Microsoft's Program Install and Uninstall troubleshooter

   Microsoft's page offers the download under its Windows 10 tab. Microsoft says it fixes corrupted registry keys on 64-bit systems, corrupted registry keys that control update data, and problems that prevent programs from being installed, completely uninstalled or updated, or that block uninstalling through Add or Remove Programs. On Windows 11 the same page gives the Settings steps instead.

   To undo: The troubleshooter has no undo of its own, which is why a restore point comes before it.

5. 05

   If the service still cannot be reached, ask support before reinstalling Windows

   Microsoft's message tells you to contact your support personnel, and its page for blocked installs ends with contacting the app publisher or, as a last resort, Reset this PC with Keep my files. We list no registry edit here because Microsoft's current documentation gives none for this error.

   To undo: Reset this PC cannot be undone and removes installed programs: it is the last step, not a routine one.

Check it yourself, without changing anything

1. 01

   Read the service's configuration (Command Prompt)

   On Windows 11 build 26300 we read START_TYPE 3 DEMAND_START (Manual), the binary path C:\WINDOWS\system32\msiexec.exe /V, the account LocalSystem and a dependency on RpcSs. Nothing is changed.

   sc.exe qc msiserver

   cmdCopy
2. 02

   Read its state (PowerShell)

   Stopped with StartType Manual is what we found on a PC where nothing was installing. Disabled is the state Microsoft's message asks you to rule out.

   Get-Service msiserver | Format-List Name, DisplayName, Status, StartType

   PowerShellCopy