The application has failed to start because the side-by-side configuration is incorrect

Ugh, yeah one of those… alright let’s have a look…

# install your service
C:\Windows\Microsoft.NET\Framework[64]\[version]\InstallUtil.exe [path to application]

# uninstall your service
C:\Windows\Microsoft.NET\Framework[64]\[version]\InstallUtil.exe /u [path to application]

So after (successfully) installing it, it does not want to start, so we have to do some tracing.

Eventlogs tells you only so much unfortunately so we look in the SxsTrace.exe  for help

# start trace
C:\windows\system32\SxsTrace.exe Trace -logfile:log.etl

# try to start your service
# press ENTER to stop the trace

# parse the trace logs
C:\windows\system32\SxsTrace.exe Parse -logfile:log.etl -outfile:SxSTrace.txt

This will open the SxSTrace.txt file which will have all the information about the error.

If that did not create any helpful information (but I hope it did) there are other steps that might help:

Sfc /scannow
sfc /scannow /offbootdir=c:\ /offwindir=c:\windows (If above fails)

and let’s try DISM

DISM.exe /Online /Cleanup-image /Scanhealth
DISM.exe /Online /Cleanup-image /Restorehealth

Last resort options are a System Restore or updating .NET to the latest version.