Deleting Windows backups after specified media type is invalid message

When I checked on the status of the weekly backup process on a Microsoft Windows 10 system by issuing a wbadmin get versions command at a command prompt, I saw that no backups had been created since July of 2018.

Udemy Generic Category (English)120x600

Microsoft Windows [Version 10.0.17134.285]
(c) 2018 Microsoft Corporation. All rights reserved.

C:\WINDOWS\system32>wbadmin get versions
wbadmin 1.0 - Backup command-line tool
(C) Copyright 2013 Microsoft Corporation. All rights reserved.

Backup time: 7/17/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 07/17/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {76dc6b17-ef40-418f-b13a-a332f3f18c66}

Backup time: 7/24/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 07/24/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {f394de8f-b3e2-4cc0-a2ee-ffb12448f1c6}

Backup time: 7/31/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 07/31/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {275475f1-22d9-455d-893b-f327b8069f99}

Backup time: 8/7/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/07/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {58902ac7-c0aa-4384-9abf-b96e89fe1954}

Backup time: 8/14/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/14/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {7600fdeb-9722-4f0d-9647-6a5a22613a40}

Backup time: 8/21/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/21/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {05e8eefe-486f-4286-bf7a-57ca7ba192e6}

Backup time: 8/28/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/28/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {cc0c16df-4eb2-43ca-bb40-4d02928e7617}

Backup time: 9/4/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 09/04/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {98c0f7a3-ca59-4c78-b4c3-5ff716a60bf2}

Backup time: 9/11/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 09/11/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {b066d090-fd1f-44e2-9899-b5defe860e65}

Backup time: 9/18/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 09/18/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {88b6a6aa-dce0-439b-96b8-98e1038411cd}

Backup time: 5/27/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 05/27/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {e7999e64-18ef-4ffe-826f-63460ae10a95}

Backup time: 6/3/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/03/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {ed35b3bb-5409-4351-82b3-42829908d5b2}

Backup time: 6/10/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/10/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {8dd10f96-c62e-42e9-9d68-0947f529db52}

Backup time: 6/17/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/17/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {0ebd7188-35b3-4317-bb20-b718dfd35789}

Backup time: 6/24/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/24/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {93803f25-207b-410d-891f-d1e8244236aa}

Backup time: 7/1/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 07/01/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {76022746-9b00-4380-a08b-d9a9b5bdd2d8}

Backup time: 7/8/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 07/08/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {030fb852-6e15-4ad3-8acb-e0b0d0057e87}


C:\WINDOWS\system32>

When I checked the free space left on the drive on which the backups were stored from the Windows File Explorer, I saw there was only a few megabytes of free disk space left, so I attempted to delete some of the prior backups with the wbadmin command, but I was unable to delete them with the message "failed with error: The specified media type is invalid" message appearing.

C:\WINDOWS\system32> WBADMIN DELETE BACKUP -keepVersions:7
wbadmin 1.0 - Backup command-line tool
(C) Copyright 2013 Microsoft Corporation. All rights reserved.

Enumerating backups...
Found 17 backups,
7 will be left after the delete operation.
Do you want to delete the backups?
[Y] Yes [N] No y

Deleting backup version 07/17/2016-23:00 (1 out of 10)...
The operation to delete backup version 07/17/2016-23:00
failed with error: The specified media type is invalid.
.
Do you want to delete the entry of the backup in the catalog?
(This option will not free space on the storage location.)
[Y] Yes [N] No y

Deleting backup version 07/24/2016-23:00 (2 out of 10)...
The operation to delete backup version 07/24/2016-23:00
failed with error: The specified media type is invalid.
.
Do you want to delete the entry of the backup in the catalog?
(This option will not free space on the storage location.)
[Y] Yes [N] No y

Deleting backup version 07/31/2016-23:00 (3 out of 10)...
The operation to delete backup version 07/31/2016-23:00
failed with error: The specified media type is invalid.
.
Do you want to delete the entry of the backup in the catalog?
(This option will not free space on the storage location.)
[Y] Yes [N] No Y

Deleting backup version 08/07/2016-23:00 (4 out of 10)...
The operation to delete backup version 08/07/2016-23:00
failed with error: The specified media type is invalid.
.
Do you want to delete the entry of the backup in the catalog?
(This option will not free space on the storage location.)
[Y] Yes [N] No
Deleting backup version 08/14/2016-23:00 (5 out of 10)...
^C
C:\WINDOWS\system32>

So I then attempted to delete the old backups through the graphical user interface (GUI) for the backup program. I was able to successfully delete them by that method and free disk space. You can take the following steps to do so:

  1. Right-click on the Windows Start button.
  2. Click on Update & Security.

    Windows Settings

  3. Click on Backup.

    Windows Update - Backup

  4. Click on Go to Backup and Restore (Windows 7).

    Backup

  5. At the "Back up or restore files" window, click on the Options button next to the message "The disk that your backups are being saved on doesn't have enough free space."

    Backup or restore your files

  6. At the "Check your backup disk space" window, click on Manage backup disk space.

    Check your backup disk space

  7. At the Manage Windows Backup disk space window, click on View backups to free up disk space by deleting data file backups.

    Manage Windows Backup disk
space

  8. At the "Select a backup period to delete" window, you can click on entries to select which backups to delete.

    Select a backup period to delete

    When you've selected one by clicking on it, click on the Delete button to remove it.

  9. When asked "Are you sure you want to delete this data file backup?", click on Delete.
  10. When you see the "Backup has been deleted" message, click on the Close button.

    Select a backup period to delete

  11. When you have finished deleting all of the old backups that you wish to remove, click on the Close button.

    Backups deleted

After I had deleted all but 3 of the prior backups, I right-clicked on the backup drive in the Windows File Explorer and selected Properties. I then saw 1.02 TB of disk space was free.

Drive K properties

When I checked the versions again with the wbadmin get versions command, though, it showed versions that I had deleted as still being present.




C:\WINDOWS\system32>wbadmin get versions
wbadmin 1.0 - Backup command-line tool
(C) Copyright 2013 Microsoft Corporation. All rights reserved.

Backup time: 8/7/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/07/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {58902ac7-c0aa-4384-9abf-b96e89fe1954}

Backup time: 8/14/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/14/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {7600fdeb-9722-4f0d-9647-6a5a22613a40}

Backup time: 8/21/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/21/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {05e8eefe-486f-4286-bf7a-57ca7ba192e6}

Backup time: 8/28/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 08/28/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {cc0c16df-4eb2-43ca-bb40-4d02928e7617}

Backup time: 9/4/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 09/04/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {98c0f7a3-ca59-4c78-b4c3-5ff716a60bf2}

Backup time: 9/11/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 09/11/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {b066d090-fd1f-44e2-9899-b5defe860e65}

Backup time: 9/18/2016 7:00 PM
Backup target: 1394/USB Disk labeled My Passport(K:)
Version identifier: 09/18/2016-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {88b6a6aa-dce0-439b-96b8-98e1038411cd}

Backup time: 5/27/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 05/27/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {e7999e64-18ef-4ffe-826f-63460ae10a95}

Backup time: 6/3/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/03/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {ed35b3bb-5409-4351-82b3-42829908d5b2}

Backup time: 6/10/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/10/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {8dd10f96-c62e-42e9-9d68-0947f529db52}

Backup time: 6/17/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/17/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {0ebd7188-35b3-4317-bb20-b718dfd35789}

Backup time: 6/24/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 06/24/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {93803f25-207b-410d-891f-d1e8244236aa}

Backup time: 7/1/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 07/01/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {76022746-9b00-4380-a08b-d9a9b5bdd2d8}

Backup time: 7/8/2018 7:00 PM
Backup target: 1394/USB Disk labeled Seagate Backup Plus Drive(K:)
Version identifier: 07/08/2018-23:00
Can recover: Volume(s), File(s), Application(s), Bare Metal Recovery, System State
Snapshot ID: {030fb852-6e15-4ad3-8acb-e0b0d0057e87}


C:\WINDOWS\system32>

Reference:

  1. Deleting old Windows backups with wbadmin
  2. Determining last Windows backup time from a command prompt
  3. Checking the status of a server backup with wbadmin