Hi Greg,
Thank you for replying. I took a fresh look after reading your suggestions.
This isn't a case of an external drive not being detected.
I should note that I could not access the D:\ partition root directory normally through the File Explorer (even starting it with a right-click and run as Administrator). However, with the regular File Explorer (my account is an Administrator) I can type in any first level subdirectory and access that, e.g. D:\Temp and E:\Temp. I could not access the root directory. I could use Notepad with normal privileges to open a file for which I know the filename that is in the root directory of the partition (I can know that filename from seeing it in Power Shell).
The main partitions on the disk in the USB shell are D: and E:. Running Computer Management (normally) they appear in Disk Manager and are labeled appropriately. The Properties dialog boxes show the amount of disk used and space available, unlike the properties dialog from the File Explorer.
I started to go through your suggestion to changing drive letter D: to P:, but there
were messages:
/!\ some programs that rely on drive letters might not run correcty. Do you want to continue? Yes.
next dialog:
The volume <volume_label> (D:) Simple Volume is currently in use. If you continue, the new drive letter will be assigned, but you can still use the old drive letter to access the volume until you restart your computer. The old drive letter will not be available for assignment until you restart.
WARNING: Changing the drive letter of a volume might cause programs to no longer run. Do you want to continue?
No, not yet. Unmounting and remounting the drive physically didn't work, so I don't think doing it logically by changing the drive letter will work either.
However, I have Cygwin on this machine. I notice in the regular cygwin shell, I see
Jon@Vivo /cygdrive
Jon@Vivo /cygdrive
$ ls -la
total 16
dr-xr-xrx 1 Jon None 0 May 3 20:29 .
drwxr-xr-x+ 1 Jon None 0 Nov 25 2017 ..
d---r-x---+ 1 NT SERVICE+TrustedInstaller NT SERVICE+TrustedInstaller
0 May 2 17:01 c
Jon@Vivo /cygdrive
and when right-clicking and running a cygwin shell as Administrator I see:
Jon@Vivo /cygdrive
$ ls -la
total 32
dr-xr-xr-x 1 Jon None 0 May 3 20:28 .
drwxr-xr-x+ 1 Jon None 0 Nov 25 2017 ..
d---r-x---+ 1 NT SERVICE+TrustedInstaller NT SERVICE+TrustedInstaller
0 May 2 17:01 c
drwxrwx---+ 1 Jon SYSTEM 0 May 3 20:10 d
drwxrwx--- 1 Administrators SYSTEM 0 May 2 17:00 e
Jon@Vivo /cygdrive
$
I thought that changing these permissions might help, but it turned out these permissions were unaffected by the fix.
I looked at the groups
Jon@Vivo /cygdrive
$ groups Administrators
Administrators : Administrators Authenticated Users
Jon@Vivo /cygdrive
$ groups None
None : None Authenticated Users
Jon@Vivo /cygdrive
$ groups "NT SERVICE+TrustedInstaller"
NT SERVICE+TrustedInstaller : NT SERVICE+TrustedInstaller Authenticated Users
The fix:
I plugged in another USB shell with a drive, one that works properly. I right-clicked on the newly attached G: drive and looked in the Properties dialog at the Security tab. It lists groups Authenticated Users, SYSTEM, Administrators (VIVO\Administrators), and Users (VIVO\Users), where VIVO is the host name of my computer. Others should substitute their own host's name.
The process for D: may have been affected by running Take Ownership. I only ran Take Ownership on the D: drive, so readers others may want to look at the process on drive E: below to save time. I did not run Take Ownership on E:. It took a long time to run on D:.
When I right-clicked on the D: drive for the Properties dialog box, the Security Tab only had SYSTEM and Administrators (VIVO\Administrators). Also, the permissions did not show all the checkmarks as G: had. So, I decided to try to edit the permissions so D: would match permissions for G:.
In the working drive G:, SYSTEM had permissions checked under Allow: {Full control, Read &execute, List folder contents, Read, and Write}.
The drive D: didn't. So, I tried to set them. It didn't seem to work, so I thought maybe I should set the Administrators settings first.
At some point I did add VIVO\Jon, my own account which is in Administrators. That shouldn't be necessary, but users can try that. I removed it later since the Administrators group permissions are passed on to members of the group, and my account is a member of the group.
On the working drive G:, the Administrators (VIVO\Administrators) group had Allow checked for all permissions except the special permissions: It had checked {Full control, Modify, Read &execute, List folder contents, Read, and Write}, so that's what to match on drive D:. I chose Continue at the error dialog and continued clicking Continue many times. At one point when I thought I was done, the Apply button was still active, so I clicked Apply and continued. Then when the Apply button was no longer active, I clicked OK, and closed the dialog box.
I continued and added Authenticated Users so that group would have the permissions of {Modify, Read & Execute, List folder contents, Read, and Write}, as G: had for that group. (The C: drive does not have the same permissions for the groups.)
I saw that SYSTEM had permissions showing as check marked: {Full Control, Modify, Read & Execute, list folder contents, Read, and Write (but not Special Permissions}} as was showing for Administrators. So D: matched G: for SYSTEM.
I was then able to see the drive space used and space free in File Manager for drive D:. I reopened the Properties Dialog for D: and continued matching the working set of permissions on drive G:.
The last group to add was Users (VIVO\Users) so it would have the permissions on D: for Read & Execute, List folder contents, and Read.
(At this point I removed the VIVO\Jon entry because it is covered by VIVO\Administrators.
I double-checked the permissions. I checked permissions on C:. They differed. On C:, Authenticated Users has only special permissions. All the other groups on C: should match the permissions on drive G:
Administrators (VIVO\Administrators) has check marked: Full control, Modify, Read & execute, List folder contents, Read, and Write. Special permissions is not check marked.
SYSTEM also has check marked: Full control, Modify, Read & execute, List folder contents, Read, and Write. Special permissions is not check marked.
Users (VIVO\Users) has three permissions check marked:
Read & execute, List folder contents, and Read.
For drive E:, I repeated the process used for D:. and it went back to normal in File Explorer too. The process was a little different, probably because I hadn't run Take Ownership. It was much faster.
Right-click the drive to get the Properties dialog. Go to the Security tab and click the Advanced button. It said Owner: Unable to display current owner. On the Permissions tab, click Continue. I checked working drive G: for comparison.
On E:, start by highlighting the Administrators (VIVO\Administrators) group, and click Edit. If necessary, click Select a principal. Choose Type Allow, and Applies to: This folder, subfolders, and files. Choose Full control, Modify, Read & execute, List folder contents, Read, and Write. Click OK.
Repeat for SYSTEM.
Then select Add, Select a principal, type Authenticated Users, click Check Names, click OK. Go back to Authenticated Users and click Modify. The Write box gets a check mark too. The type is Allow, and the Applies to: is This folder, subfolders, and files. The permissions for Authenticated Users are: Modify, Read & execute, List folder contents, Read, and Write.
Click Add, Select a principal, Enter VIVO\Users, (replacing VIVO with your host name) . Click Check Names, OK. Make sure Read & execute, List folder contents, and Read are checked. Click OK.
I checked the permissions against the permissions on G:.
In the Advanced permissions tab, G:\ shows:
Allow, Administrators (VIVO\Administrators, Full control, None, This folder, subfolders and files.
Allow, SYSTEM, Full control, None, This folder, subfolders and files.
Allow, Authenticated Users, Modify, None, This folder, subfolders and files.
Allow, Users (VIVO\Users), Read & execute, None, This folder, subfolders and files.
Match this, click Apply and Continue each time needed, and finish up with OK to close the dialog box. Reopen the drive's Properties Dialog box to the Security tab and double check.
The File Explorer now shows the information for drive E:.
What about drive C:?
The permissions were different. I was able to compare with my Windows 10 tablet.
Right-click drive C: Choose Properties. Choose the Security Tab.
Look at the Administrators group first. Full Control through Write. That matches.
Look at the SYSTEM group/user. Full Control through Write. That matches.
Look at the Authenticated Users. That says Special Permissions only. That matches.
The Users (VIVO\Users) group shows Read & Execute, List folder contents, and Read.
Finally, I've got normal access back for those partitions.
