We have a Windows 2012 server running SharePoint Foundation 2010 (which will eventually be migrated to SharePoint 2013 Enterprise).
In the meantime we seem to be experiencing some odd issues, which initially looked to be related to path or URL length, but now I am unsure.
For example, there is a site:-
When the person who "owns" this site attempts to upload a file called "Daily Income and Banking Sheet Master.xls" he gets the following error:-
The URL 'Income Daily Sheets/Daily Income and Banking Sheet Master.xls' is invalid. It may refer to a nonexistent file or folder, or refer to a valid file or folder that is in the current Web.
This user has Full Control and Read permissions on the site. I log on using the administrator account (with no site specified permissions) and can upload a file with exactly the same name to the same site without any issue.
This has happened (so far) with two specific users on two different sites within SharePoint 2010.