Error 1935: Error During the Installation of Assembly Component

What causes Error 1935

• Microsoft's article on error 1935 with Office says the issue may be caused by interference between Windows Installer (msiexec.exe) and Windows Search (SearchIndexer.exe), or another module, in the assembly file copy process.
• The same article says it may also occur when other updates are applied, for example a hotfix for .NET Framework components, and gives repairing or updating the .NET Framework as a method.

How to fix Error 1935, safest step first

Microsoft's article is written for Office setups. In its order:

1. 01

   Restart the computer and run the setup again

   Microsoft calls this the quick first step for error 1935.

   To undo: Nothing to undo.

2. 02

   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.

3. 03

   For Office setups only: delete the APPMODEL registry subkey

   Microsoft's article says that deleting HKEY_LOCAL_MACHINE\SOFTWARE\MICROSOFT\APPMODEL should allow you to install Office, and warns that serious problems might occur if you modify the registry incorrectly. Export the subkey first (right-click it in Registry Editor > Export), then delete it, restart and run the Office setup again. Do not use this method for other programs.

   To undo: Double-click the .reg file you exported to put the subkey back.

4. 04

   Repair or update the .NET Framework

   Microsoft's article says the Microsoft .NET Framework Repair Tool can repair .NET Framework components. Its System Update Readiness tool method is for Windows 7 and Windows Vista only.

   To undo: The repair tool has no undo; the restore point from the earlier step brings back the previous state.

5. 05

   Try again in a clean boot

   A clean boot starts Windows with only Microsoft services and no startup programs, so another program cannot interfere. Follow Microsoft's clean boot article, then run the setup or removal again.

   To undo: Microsoft's article ends with the steps to reset the computer to start normally: turn the services and startup items back on, then restart.

Check it yourself, without changing anything

1. 01

   Find the message in the Application log (PowerShell)

   Microsoft documents that errors from the installer's Error table are logged with an event ID equal to the error number plus 10,000, so 1935 is event 11935. Nothing is changed.

   Get-WinEvent -FilterHashtable @{ LogName='Application'; ProviderName='MsiInstaller'; Id=11935 } -MaxEvents 5 |
     Format-List TimeCreated, Message

   PowerShellCopy
2. 02

   Read what Windows Installer logged (PowerShell)

   Microsoft documents event 1033 (installation completed with status) and 1034 (removal completed with status): each names the product, its version and the status number, which is 0 on success. Nothing is changed.

   Get-WinEvent -FilterHashtable @{ LogName='Application'; ProviderName='MsiInstaller'; Id=1033,1034 } -MaxEvents 10 |
     Format-List TimeCreated, Id, Message

   PowerShellCopy