Hi I am doing an upgrade and it has gone through but I keep getting this error and I dont know what to do and the site is down 

 

[Template core/admin/global/globalTemplate is throwing an error. This theme may be out of date. Run the support tool in the AdminCP to restore the default theme.]]

Is this template customized? If yes, please make backup of it and revert to default. Then check again.

I have done the upgrade and cant access anything now 

 

The template was customised

 

 

Quote

Constant - RECOVERY_MODE
Use - Used for recovery of the system when failure occurs in 3rd party items, preventing ACP access
Example value - TRUE

 

I have also just lost access to my ACP days after upgrading. I have no idea what is going on, but I am not a happy customer right now. 

You could upload the full default theme which would give you access to your ACP again.  Then you could alter the custom theme as needed and then set the custom as the default.