I don't understand what you are trying to achieve? Are you trying to change the format of the log; the results of the log?
I suggest you refer to https://support.smartbear.com/testcomplete/docs/reference/project-objects/test-log/log-params/index.html and also look at the examples
In our Project we are creating the folder for a log using Log.AppendFolder() and pushing the entire messages into that Log, In end of the Script Execution I need to check that if that folder contains any Error message I need to change the Folder Background color to Red. Is that possible?
The attributes that can be changed are shown in the link that I've provided, and I don't think the folder colour can be change.
https://support.smartbear.com/testcomplete/docs/testing-with/log/summary.html clearly shows what has passed or failed.
You can only set log attribute before using the log actions to append folder Log.CreateNewAttributes Method | TestComplete Documentation
Mind you as rraghvani stated when error exist it is well marked on the folder.
