Yesterday, we decided to upgrade all of our 3 XenServer 6.1 servers to the latest up to date Hotfix level. That included all the current hotfixes available.
Everything was done according to the upgrade path provided with disabling of HA and starting with the XenServer Master server.

Now, everything looked to go okay. But after the servers all had rebooted they refused to leave maintenance mode.
We tried litterary everything there was of commands, that are safe to run, still no go, XenCenter refused to connect to the pool, but we were able to SSH our way in! 

After a GTM session with Citrix support, we decided to reinstall the entire xenserver pool. The issue seems to be around XS61E009 and XS61E010.

The new install is with XenServer 6.1 and with all hotfixes, patched pr server, before joining them to a new xenserver pool.

So, we started to attach the vms from the storage, and when we tried to boot them up we ended up with a BlueScreen with error: 0x00007b.

After doing som digging around I found out that you need in some cases to do this:

Blue Screen on Booting a Windows VM

Citrix believes this issue is resolved with CTX136253 – Hotfix XS61E010 – For XenServer 6.1.0.  Citrix advises customers who have experienced this issue and are running XenServer 6.0.2 Tools, including XS602E009, to install (1) the CTX136252 – Hotfix XS61E009 – For XenServer 6.1.0 on your hosts first and then upgrade your VMs to the Tools contained in XS61E010. You do not need to uninstall a previous version of XenServer Tools before upgrading to XS61E010 Tools.

The following procedure remains in this document as a precaution in case customers encounter blue screens when booting a Windows VM.

1. Note the VM’s unique identifier (UUID): in XenCenter, select the VM in the left-hand tree view. Click the General tab and record the UUID shown. You can also obtain this by using the xe vm-list command.
2. Modify the VM’s device_id parameter: on the XenServer host’s console, issue the one of the following commands:
   • To set device_id to 0001 run:
     

     xe vm-param-set uuid=<vm_uuid> platform:device_id=0001

   • To set the device_id to 0002 run:
     

     xe vm-param-set uuid=<vm_uuid> platform:device_id=0002

3. Reboot the VM.

Read this CTX article before updating!

If you have multiple disks attached to the vm in question that gets the bluescreen, then you need to initialize the disk with the disk manager in Windows Server.

PS. This article may be updated soon, due to the fact that we are not sure if we have encountered all things to restore our environment 100% yet.

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