Unable to create a directory for iCloud Photos. Restarting your computer might... (Error 5)

The original thread is here and is now locked.

https://www.dropboxforum.com/t5/Create-upload-and-share/Unable-to-create-a-directory-for-iCloud-Photos-Restarting-your/td-p/656087

The basic problem that if you have Dropbox installed on Windows 10/11, and you have the Windows Pictures junction pointing to a directory under your Dropbox installation, and you then install iCloud Photos, iCloud will then attempt to create its folders in the wrong place, resulting in a recurring "Unable to create directory" error message from iCloud.  I am posting my workaround for anyone else who ran into this.

It appears that iCloud Photos uses the Windows Pictures junction as its root folder for photos on installation.  So the basic idea is to redirect the junction temporarily to another location.  The steps follow.

1. Uninstall iCloud.

2. Disable Dropbox syncing.

3. In Windows Explorer, in the left pane, right-click on Pictures, select Properties, and in the dialog box that comes up, go to the Location tab.  Make a note of the folder location.

4. Change the folder to a place that makes sense for picture storage and is outside your Dropbox location.  In my case, the folder was initially set to C:\Users\<username>\Dropbox\Photos and I changed this to C:\Users\<username>\Pictures.  It will ask you if you want to relocate your files to the new directory; don't do this.

5. Reinstall iCloud enabling the Photos option, and it will create its folders under the folder you just specified.

6. Restore the former location of the Pictures junction by reverting the edit you performed in steps 3 and 4 above.  Again, it will ask you if you want to relocate your files, and again you should not do this.

7. Re-enable Dropbox syncing.

Going forward iCloud and Dropbox will then each sync to their respective directories.