After syncing folders on local drive, I can't copy them to a different location

[travis f.2]

I synced some large folders to my local computer and would like to copy them to a new location.     When I attempt to copy the files,  it begins placing the main folder and a few other files then immediately displays the following error:

" An unexpected error is keeping you from copying the file.  If you continue to receive this error, you can use the error code to search for help with this problem"  Error 0x80070780: The file cannot be accessed by the system"

what I've done: 

Once I synced the online Dropbox files,   I disconnected the account from the drive to reduce the likelihood of accidental deletion.

Restarted computer

[Здравко]

Do you use Smart Sync?!

[travis f.2]

I don't know what that is... so probably no. 

[Rich · Accepted solution]

Were the files marked as Local, or Online-only? If they were Online-only then what you synced were just the placeholders for the files. You need to make sure the files are fully synced to your local drive and display a green check mark. Only then are the actual files on your computer, at which point you can move or copy them as needed.

• https://help.dropbox.com/installs-integrations/sync-uploads/smart-sync

[travis f.2]

Thanks for help!