cannot copy folder/file to external drive

I have been able to copy most folders/files to external drive successfully but I'm unable to copy 2 particular folders(I don't understand significance of data in these folders, but want to copy them just in case it is important).("folder/file cannot be handled because you do not have permission to read it"). Tried changing read/write permission via properties. Tried using Chmod/Chown commands.Tried nautilus. Only these 2 folders are locked. How do I unlock these folders so I can copy them to external drive? Why are only these 2 folders locked?