The recent Windows 10 Anniversary Update appears to be causing webcams to freeze up and crash.
Thurrott.com says that there could be millions of people affected by this issue. Problems seem to have arisen as a result of how the OS update changes the way in which webcams are allowed to stream video.
A Microsoft engineer who took to the official support forums says that a fix for the problem is on the way. This fix will hopefully be released in September, according to the employee.
Until the fix is released, you may have to do without video calling. Microsoft told Gizmodo that only "a small number" of users have been affected, a statement in contrast to Thurrott’s previous prediction.