The entire path can’t cross 400 characters. It is very important to know that the entire path includes your file’s name as well as the URL (including folder name, onedrive.live.com, etc.).

Long file names superseded the eight-plus-three (8.3) character limitation used in 16-bit DOS and Windows 3.1. Long file names are supported in Unix, Mac and Windows starting with Windows 95.

The 8-character file names originating with DOS and also used in Windows. See Win short file names. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission ...

Typing a file name is easy when the name is short, but long, complex names with special characters are more difficult. The good news is you can copy file names just like normal text within Windows ...

How to Encrypt File Names. Now more than ever, it is important to protect your digital assets -- especially if you have a laptop. Whether your goal is to guard your financial data or keep nosy ...

To avoid that confusion, the OS simply bans the backslash () from file names. Frankly, I wish Microsoft was stricter about this sort of thing, and didn’t allow us to use periods (.) in file names.