The items you see in the Hide Folders window are just aliases representing the original items present in your disk. It is possible, in some circumstances, that aliases lose the link to the original items.
In order to recover not listed and hidden items, do as follows:
- If you don't have Hide Folders installed on your computer, download it the latest version from this page: https://altomac.com
- Launch the downloaded app.
- Press and hold the Option-key of the keyboard and in the Action button (highlighted in the image below) choose "Add Items".
- On the dialog window that pop-ups you will be able to select either a visible or an invisible folders and files. Please note that the names of invisible items could begin with a dot.
- Make visible the items you chose using the Show button.
Please note that this app uses the standard functionality of macOS to make files and folders invisible. The files and folders that are hidden, remain in the same place they were in when they were visible, and they move when you move the folders that contain them and are also copied and deleted along with the folders that contain them.
Also notice that all the files and folders contained in a folder made invisible are themselves invisible. For example if a file is located in an invisible folder, to make the file visible you need first to make visible the folder that contains the file.