issue with portable hdd. the problem is just i cant access the root folder, and i have access to sub folders. already used chkdsk?

Try to see if this works.

https://www.laptopmag.com/articles/take-ownership-...

You need to give yourself ownership of root folder. Follow the steps in the following article, depending on whether you're using Windows 10, 7, or XP, and ignore the first solution which is an ad for a paid-for program that can do what you can do by yourself using the instructions in the later sections of that article.

https://www.stellarinfo.com/blog/fix-inaccessible-...

Sounds like a corrupted fat table. If chkdsk did not resolve the answer, your only option is to copy off what you can from the sub folders and then reformat the drive.