Problem upgrading from 15.10 to 16.04

[Nils Kassube]

Bob wrote:
> Upgrading from 15.10 to 16.04 there was an error, if there was a
> message I did not see it because I let the upgrade run overnight . 
> The first boot after the upgrade I got the message:
> 
> Sorry the application gacutil.exe has stopped unexpectedly
> 
> Searching it appears to be a windows program!  

Not exactly - it is part of mono, which is an open source implementation 
of Microsofts .NET framework. 

> Now at every boot I get
> a popup to report a problem but no indication what the error is.
> 
> What commands do I need to do to try a get the package database
> checked and to get whatever failed the first time redone?

Try these commands in a terminal:

sudo dpkg --configure -a
sudo apt-get install -f


Nils