ParaFoam ...
 

Hello,
I am running a heat transfer problem. I have set up the case but when I am opening the case in paraFoam it is showing following problem:-

stripInvalid() called for invalid fileName T~

for debug level (=2) >1 this is considered fatal
Aborted

What is this error and how can it be rectified?

Greetings rajcfd and welcome to the forum!

It's simple: you edited the file "T" with a text editor that creates backups of the files when saving. Therefore, you have a file named "T~" somewhere next to the "T" file.
Then OpenFOAM's reader for ParaView is complaining about this "T~" file, because of the tilde "~" character.

The solution is to remove the file "T~" and the problem will be solved.

Check the options in your text editor to not save backups of files.
And if you do want to keep track of the changes you make to the case, I suggest that you study and use a source revision management software, such as Git or Mercurial ;)

Best regards,
Bruno