Hello Maro,
I would like to know some information about the issue so that we could help you better.
Did you make any hardware or software changes to your device prior to the issue?
I appreciate you for providing details about the issue and your efforts towards resolving it.
I also realize the inconvenience you are experiencing due to folder permission issue. I will certainly help you.
This issue may occur either if you are not logged in to Windows as an administrator or if you do not have proper
permissions to access or modify files and folders in Windows.
I would suggest you to use steps provided in this article and check if it helps.
Refer:
"Access Denied" or other errors when you access or work with files and folders in Windows
https://support.microsoft.com/en-us/kb/2623670
I hope this information helps.
Please do let us know if you need any further assistance.
Thank you