windows 10 - all previous VMs work - error adding a new one

[ident]

When i try to create a new windows 7 VM on my windows 10 i get errors when trying add the iso. When you click the browse icon i get

Failed to open a session for the virtual machine windows 7.

The VM session was aborted.

Result Code: E_FAIL (0x80004005)
Component: SessionMachine
Interface: ISession {7844aa05-b02e-4cdd-a04f-ade4a762e6b7}

i know windows 10 is not supprted yet but how come the old vms work?

[mpack]

This problem has already been reported: the only way to attach an ISO to a VM (v5.0.0 on Win10 host) is to use the settings|Storage dialog before the VM starts. There are unconfirmed reports that not all ISO variants are affected, but so far nobody has responded to requests to pin it down.

[ident]

Thank you very much