The URL is invalid, it may refer to a nonexistent file or folder or refer to a valid file that is not in the current Web

Last week one of my clients reported that they get the below error when they tried to Check In\Check Out documents which were of large size.

ERROR - "The URL is invalid, it may refer to a nonexistent file or folder or refer to a valid file that is not in the current Web"

I did research the web for answers and i found alot of them like this which talks about less space in SQL and many others.  Unfortunatey none of them worked for me so i started testing on my Laptop in order to identfy the differences between my Laptop and what my client was using.

Test 1 - First test was to check Windows Service Pack as suggesed by one of the forums. Well we both had the same service pack.

Test 2 - Next on the list was to check the Office Version and that's what was the cause of our issue. My client was using Office 2003 and I was using Office 2010. SharePoint for some reasons was not allowing to check Out -> save changes -> check in large documents with Word 2003.

Workaround - For now users has to download the documents they had issue with and then make changes and upload them back.