Update script for service model: DevToolsService on machine:

While deploying the standard service update, among multiple issues, you may come across one related to update of Dev-Tools.

The error message will be something as Update script for service model: DevToolsService on machine:

You can find/google multiple solutions for this problem, of which one prominent solution I can highlight is to install the VSIX files manually, as documented on the docs. 

Also someone blogged another solution for this on LinkedIn, a  while back. I tried all those solutions, until nothing worked.

If you are in the same ship as I was, the support guy may tell you to deploy the new development VM, but I would suggest you try the following before you think of a new VM.

• Go to Service Drive, on the cloud deployments it is k:\
• Go into Deployable Packages Folder and Find the Package that failed, you can find it using date/time sorting.
• Find the DevToolsService Scripts and there is a PowerShell Script named as AutoUpdateDevToolsService
• Run this script manually and resume the update from the LCS.