How to Mount and Unmount a Drive or Volume in Windows  

Hello @phrab,

It's safe to delete any that are no longer be used for a drive.

You can use steps 2 and 3 in option 4 to know which "DosDevices" drive letters and "??\Volume" values below to each other to avoid deleting the ones still used.

Brink said:

Hello @phrab,

It's safe to delete any that are no longer be used for a drive.

You can use steps 2 and 3 in option 4 to know which "DosDevices" drive letters and "??\Volume" values below to each other to avoid deleting the ones still used.

This is what I see after following your steps:

Just to make sure I understand. I use C, E, H, R, & S. I also use D & T, which are not currently plugged in.
1) Should I plug those in, redo your steps, & then delete all the others?
2) If I unplug everything, reboot, delete all volumes (except C, of course) & then plug in my portable drives, can I assign the drive letters that I want without harming anything?

Thanks again!

phrab said:

This is what I see after following your steps:
Just to make sure I understand. I use C, E, H, R, & S. I also use D & T, which are not currently plugged in.
1) Should I plug those in, redo your steps, & then delete all the others?
2) If I unplug everything, reboot, delete all volumes (except C, of course) & then plug in my portable drives, can I assign the drive letters that I want without harming anything?
Thanks again!

Correct. You would want to have everything plugged in that you do not want to delete in the registry.

Anything showing "no mount points" is fine to delete if it doesn't belong to a drive you are using anymore.

If you accidently delete something you still wanted, it's no big deal since it just removes the assigned drive letter. You'll just have to manually assign the drive letter you want to use if Windows doesn't already assign in the next time you connect the drive.

Brink said:

Correct. You would want to have everything plugged in that you do not want to delete in the registry.

Anything showing "no mount points" is fine to delete if it doesn't belong to a drive you are using anymore.

If you accidently delete something you still wanted, it's no big deal since it just removes the assigned drive letter. You'll just have to manually assign the drive letter you want to use if Windows doesn't already assign in the next time you connect the drive.

I must be doing something wrong. Here's what I see & what happens.

Possible values for VolumeName along with current mount points are:

\\?\Volume{b44444fd-cd65-45a1-a662-d4026af14f27}\
C:\

\\?\Volume{4c8b0cd2-d47b-4955-8370-619e57fcad27}\
*** NO MOUNT POINTS ***

\\?\Volume{f0d2cbfb-0000-0000-0000-100000000000}\
D:\

\\?\Volume{51287cca-0000-0000-0000-100000000000}\
E:\

\\?\Volume{73cca8b4-f55b-11e6-82ca-1c1b0d68a3ad}\
H:\

\\?\Volume{6973b525-6752-47d9-9e51-b4f54ef56cec}\
*** NO MOUNT POINTS ***

\\?\Volume{cf9133d1-f54f-11e6-82c1-806e6f6e6963}\
R:\

\\?\Volume{71a9d6c9-b62b-11ea-85b7-806e6f6e6963}\
S:\

Then I issue this command:
C:\WINDOWS\system32>mountvol \\?\Volume{4c8b0cd2-d47b-4955-8370-619e57fcad27}\: /P
The filename, directory name, or volume label syntax is incorrect.

C:\WINDOWS\system32>mountvol {4c8b0cd2-d47b-4955-8370-619e57fcad27}: /P
The filename, directory name, or volume label syntax is incorrect.

This is what's left in the registry:

@phrab

It looks like you tried to unmount with the volume ID instead of drive letter in the command causing the syntax error.

https://docs.microsoft.com/en-us/win...mands/mountvol

Does all of your drives have the correct drive letters assigned to them?

Brink said:

@phrab

It looks like you tried to unmount with the volume ID instead of drive letter in the command causing the syntax error.

https://docs.microsoft.com/en-us/win...mands/mountvol

Does all of your drives have the correct drive letters assigned to them?

As far as I know, yes. The only drives that I try to keep with the same letters are C, D (external drive), E (external drive), H (thumb drive for File History), R & S (CD & DVD drives) & T (thumb drive for backup). They are all listed above, but I don't know what the other volumes are.

phrab said:

As far as I know, yes. The only drives that I try to keep with the same letters are C, D (external drive), E (external drive), H (thumb drive for File History), R & S (CD & DVD drives) & T (thumb drive for backup). They are all listed above, but I don't know what the other volumes are.

If you mean the \\?\Volume registry values, then they are just the volume ID's of your drives crossed referenced with the drive letters.

Brink said:

If you mean the \\?\Volume registry values, then they are just the volume ID's of your drives crossed referenced with the drive letters.

Sorry for being so dense. Right now, I have all drives plugged in except D & T. Are you saying that in the image:

where it says no mount points, it's just a cross reference for D & T, which are not currently plugged in? And that I should stop worrying about it?

phrab said:

Sorry for being so dense. Right now, I have all drives plugged in except D & T. Are you saying that in the image:
where it says no mount points, it's just a cross reference for D & T, which are not currently plugged in? And that I should stop worrying about it?

No worries mate.

Correct. No mount points are just drives that were previously connected and mounted with a driver letter, and are currently not connected.