Two users at MIT have reported nuisance Leash modal error dialogs while running Leash (aka MIT Kerberos Ticket Manager) on Windows. In both cases the errors started happening after a Windows 10 update in mid-February. The error dialogs say: Matching credential not found (Kerberos error -1765328243) krb5_cc_start_seq_get failed The errors do not seem to impede the operation of the app that needs tickets (SAPgui in both cases), except that the error popups happen repeatedly and steal focus. I have advised the users to fully exit the ticket manager after acquiring tickets, which I hope will work around the most annoying aspect of the problem. From code inspection, I believe the error occurs when Leash tries to update its ticket display. Leash iterates over the ccache collection, reaches the LSA ccache, and tries to iterate over the creds in that ccache. krb5_start_seq_get() returns KRB5_CC_NOTFOUND and the error pops up (KrbListTickets.cpp:do_ccache() line 223). Normally when the LSA ccache is empty, a prior call to krb5_cc_get_principal() would fail (line 212) and in that case the error dialog is suppressed. Ideally I will get confirmation that the circumstances surrounding the error are as I suspect (specifically that the users have an API default ccache and the LSA ccache is empty), account for the difference in Windows behavior which causes krb5_cc_get_principal() to succeed on an empty ccache when it used to fail, and then patch the problem. But since I cannot personally reproduce the error, there is a good chance I will simply patch Leash to suppress errors when krb5_cc_start_seq_get() fails.