Cannot read external hard disk folders created in Ubuntu

I am experiencing a problem. I tried to plug in my external hard disk on Ubuntu. I copied in to it some folders (created on Ubuntu) with files in them.

Then, I plugged it on Windows and I wasn't able to copy or modify any of the copies folders or sub-folders. I could access my files (and modify them), but I couldn't modify or copy any of the folders or sub-folders.

I tried formatting my computer's and the external hard disk, that did not make a difference.

What should I do?

wimvds --> Thanks for your answer, first of all :) Yes! I did. I always use "Unmount" on linux as well as on windows...

Misery --> No errors are promoted during the copy process. What do you mean by saying "attributions"?? :/

Solution 1:

As others have said this is file permissions.

Use Microsoft's "xcacls" (a downloadable tool by Microsoft for Windows sysadmins) because I believe it's a Windows issue. I used to see this on Windows Servers sometimes when the ACL (Access Control List) is borked.

Take ownership of everything (important) and then assign 'full control' access level.

You shouldn't have to do it each time.