If the memory leak is intensive, it can cause the program to crash or even make the whole computer freeze. The most common reason programs have memory leaks is due to a programming error where unused memory is not allocated back to the system.Memory leaks are a class of bugs where the application fails to release memory when no longer needed. A large leak might result in unacceptable response times due to excessive paging. The windows 10 security update (KB4100375) rescheduled because of above reasons.
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Microsoft explains why Windows 10 Spring Creators Update delayed