Dear respected Shubhamv85,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
I’m sorry you’re having a problem but based on your description we can work together to resolve it.
For the situation you encountered, we deeply understand the inconvenience caused and apologize for it.
As per your description, may I know if you click on "Copy to Folder" and navigate to location are you able to save file to still getting a same error message?

Also, may I know does this occur on a specific PowerPoint file? if you create a new sample PowerPoint file (for test purpose) and verify the result with us. It will help for us to narrow down your problem.
In the meantime, to confirm whether this is a bug in a specific version, please provide us the version information. To check version: Open PowerPoint>File>Account>Product Information and capture a full screenshot and share here and we will be tested on that version and verify the result with you.
Please understand that our initial reply may not always immediately resolve the issue. However, with your help and more detailed information, we can work together to find a solution.
I'm sorry and I apologize for that.
Appreciate your patience and understanding and thank you for your time and cooperation.
Sincerely,
Waqas Muhammad