Recreating the GitHub Actions Runner service manually on Windows when an upgrade has deleted it.

[ColinFinck]

Windows 11 24H2 is one of those Windows upgrades, which (again!) recreates the entire HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services registry key from scratch. This is what happened to me yesterday. As a result, my manually installed GitHub Actions Runner service was gone.

Even worse, there is currently no official way to reinstall the GitHub Actions Runner service without reconfiguring it from scratch with new credentials.
I just wanted to get the service up again without reregistering it at GitHub. Therefore, I had to manually reinstall it with sc. I'm hereby sharing how I did that:

First of all, when Windows recreates the Services key, it backs up the old one at least. You can find it at C:\Windows.old\Windows\System32\config\SYSTEM. Open regedit, go to HKEY_LOCAL_MACHINE, and click File -> Load Hive. Then select that file and enter a name for the loaded hive. I called it "sysold". Now you can navigate to HKEY_LOCAL_MACHINE\sysold\ControlSet001\Services and you should see subkeys starting with actions.runner... These are the service names. Opening one of such keys, you should also find DisplayName and ImagePath values. We need all of this for the sc call.

Then open a Command Prompt with administrator privileges and enter

sc create "<Name>" type= own start= auto binpath= "<ImagePath>" displayname= "<DisplayName>"

<Name> is the service key name, e.g. actions.runner.mine
<ImagePath> is the value of the ImagePath value, e.g. C:\actions-runner\bin\RunnerService.exe
<DisplayName> is the value of the DisplayName value, e.g. GitHub Actions Runner (mine)

Afterwards, I still needed to adjust the logon user and password. I first checked the "Owner" in the Properties -> Security -> Advanced tab of the C:\actions-runner\_work directory. I found out that it was owned by some "runner" user.
Then I opened services.msc, right-clicked the newly created GitHub Actions Runner service -> Properties -> Log On. I selected "This account" and entered the user name and password of the "runner" user.

After confirming everything and closing the dialogs, I was able to start the GitHub Actions Runner service and it worked again.