What is the scheduled task "\Microsoft\Windows\Windows Media Sharing\UpdateLibrary" on my Windows 8 computer?

"\Microsoft\Windows\Windows Media Sharing\UpdateLibrary" is a scheduled task on Windows 8 system added as part of Windows installation.

You will see "\Microsoft\Windows\Windows Media Sharing\UpdateLibrary" listed on Task Scheduler with the following information:

Name: UpdateLibrary
Location: \Microsoft\Windows\Windows Media Sharing
Description: This task updates the cached list of folders and the 
   security permissions on any new files in a user's shared media library.
Actions: "%ProgramFiles%\Windows Media Player\wmpnscfg.exe" 
Triggers: Custom event filter
History: 

Programe file information about "wmpnscfg.exe":

File name: wmpnscfg.exe
File path: C:\Program Files\Windows Media Player\wmpnscfg.exe
File size: 68096 bytes
Last modified time: 7/25/2012 11:08:52 PM
File description: Windows Media Player Network Sharing Service Configuration Application
File version: 12.0.9200.16384 (win8_rtm.120725-1247)
Company name: Microsoft Corporation

"wmpnscfg.exe" is scheduled to run on specific events.

It is recommended to keep "\Microsoft\Windows\Windows Media Sharing\UpdateLibrary" enabled as a scheduled task.

⇒System Scheduled Tasks on Windows 8

⇒⇒Windows 8 Scheduled Tasks