When you install Live Essentials or Office 365 Single Sign in Assistant they install Security Support Providers of their own, “liveSSP” and “msoidSSP” respectively. These value are added to the “Security Packages” key in: “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\”
Removing the “liveSSP” and/or the “msoidSSP” entry from the security packages key does temporary fix the problem, but if an update to office 365 or live essentials is applied then the SSP values are written back to the Security Package key and the issue occurs all over again.
Msoidssp is a SSP used to align the SSPI interface with the client so that the client can connect with the server in the secure channel, more information about this SSP in the following link: http://community.office365.com/en-us/w/office/534.aspx
In office 365, it’s already using the secure channel, msoidSSP was a second secure channel from the windows 7 client for it to drop back on to like a safety net if the it was unable to secure communicate using the normal method. Removing the registry should not impact the usage of office 365 services as long as it is able to communicate successfully without the need to drop back to the second SSP.
The bug fix should be available in App-V client 4.6 SP2.
App-V 4.6 SP2 Release notes, please read before updating to SP2: http://technet.microsoft.com/en-us/library/jj729866.aspx