Since the last time I was able to switch to another user, in my 1st computer, only Windows Defender Definitions were installed.

Currently, I'm not able to switch to another user: the computer slows down so much that 10 minutes are not enough to complete the operation. The disk activity LED, which is normally on in these operations, is off most of the time.

Nevertheless, I'm able to log off current user, and then, log on another user.

ADDED: I ran sfc.exe /scannow, but it only found 2 corrupted files, which are remanent from last failed KB3022345 installation: "utc.app.json" and "telemetry.ASM-WindowsDefault.json" (from CBS.log).

• Edited by __arpoador Wednesday, June 10, 2015 4:43 AM included sfc /scannow result

Have you run DISM? Instructions for that can be found on this wiki.

How To Enable/Disable Fast User Switching In Windows 8

Have you run DISM? Instructions for that can be found on this wiki.

SFC.exe and DISM.exe outputs, are the same for when I ran them to try to fix KB failed installation.

I ran SFC.exe, and the result is as mentioned above.

As far as I kow, DISM.exe has to do with Windows Update only, anyway, I ran DISM.exe /checkhealth, which told me the erros are fixable.

I ran DISM.exe /scanhealth, which showed to me problems related to Windows Update installation, and not to the present thread.

Running DISM.exe /restorehealth results in failure, telling could not download the files needed, and to use /source parameter.

This is the output for DISM.exe /scanhealth:

-x-

(p) CSI Payload Corrupt x86_microsoft-windows-u..ed-telemetry-client_ ... \utc.app.json
(p) CSI Payload Corrupt x86_microsoft-windows-u..ed-telemetry-client_ ... \telemetry.ASM-WindowsDefault.json
(p) CSI Payload Corrupt x86_microsoft-windows-u..ed-telemetry-client_ ... \utc.app.json
(p) CSI Payload Corrupt x86_microsoft-windows-u..ed-telemetry-client_ ... \telemetry.ASM-WindowsDefault.json

Summary:
Operation: Detect only
Operation result: 0x0
Last Successful Step: CSI store detection completes.
Total Detected Corruption: 4
 CBS Manifest Corruption: 0
 CBS Metadata Corruption: 0
 CSI Manifest Corruption: 0
 CSI Metadata Corruption: 0
 CSI Payload Corruption: 4
Total Repaired Corruption: 0
 CBS Manifest Repaired: 0
 CSI Manifest Repaired: 0
 CSI Payload Repaired: 0
 CSI Store Metadata refreshed: True

Total Operation Time: 1786 seconds.

-x-

Really nothing to do with my current problem. It seems that's only me having this problem...