Files contained in a Windows encrypted folder give error opening even after decryption

[musicollector]

I had encrypted a folder that is on a USB external drive (not a thumb drive). When I encrypted the folder, it never asked me to configure a password. However, the encryption seems to have worked as there was a lock. Now, when I decrypted the folder, it did go through the visible motions, and the lock has disappeared. However, when I try to open any file, it gives the error, "Cannot open document...access is denied". I can open all the subfolders, but I get the error only when I try to open the files. I really need to get into these documents. I regret having encrypted them in the first place.

I hope you can help me. TIA.