System.Reflection.TargetInvocationException TMPE.log is denined

Article verified: February 2022 - TM:PE 11.6.5.7

Note to TM:PE team: Check the folder path for stuff like DODI-Repacks which indicates pirated copy of the game.

Symptom

This issue is most common on Windows for users who have tried moving the game to a different drive:

A System.Exception error is shown in the game (or sometimes a System.IO.IOException error)
On inspecting your log file, you find something mentioning TMPE.log is denined

Example log messages (folder path truncated for sake of brevity):

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --->
System.TypeInitializationException: An exception was thrown by the type initializer for TrafficManager.State.GlobalConfig --->
System.UnauthorizedAccessException: Access to the path "...\Steam\steamapps\common\Cities_Skylines\Cities_Data\TMPE.log" is denied.

or:

System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. --->
System.UnauthorizedAccessException: Access to the path "...\Steam\steamapps\common\Cities_Skylines\Cities_Data\TMPE.log" is denied.

In rare cases you might get a System.IO.IOException with a log file showing things like:

System.IO.IOException: Sharing violation on path D:\SteamLibrary\steamapps\common\Cities_Skylines\Cities_Data\TMPE.log
at System.IO.FileStream..ctor (System.String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, Boolean anonymous, FileOptions options) [0x00000] in <filename unknown>:0