XML Errors in the Task scheduler

When I open the task scheduler I get a pop up telling me that the XML code contains an incorrect value, badly formatted, out of bounds or a bad node.

I get this error for the following tasks:

• VerifiedPublisherCertStoreCheck
• UserTask
• SystemTask
• Consolidator
• Background Synchronization
• HiveUploadTask

When I run Get-ScheduledTask in PowerShell I get this output:

Get-ScheduledTask : Le code XML de la tâche contient un noud inattendu.
Au caractère Ligne:1 : 1
+ Get-ScheduledTask
+ ~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (MSFT_ScheduledTask:Root/Microsoft...T_ScheduledTask) [Get-ScheduledTask], CimException + FullyQualifiedErrorId : HRESULT 0x80041316,Get-ScheduledTask

The first line is about a not expected node in the XML code.

I'm running Windows 8 Pro 64bits and I didn't get a power outage or have to hard reboot.

Open the Install.wim of your Windows 8 DVD with 7zip and extract the corrupted task to your HDD in C:\Temp.

Now add XML extension to all tasks, run task scheduler, delete the corrupted tasks and import the task again by selecting the extracted XML files.