How a small leak can bring a system to a halt
When an application needs working space, it asks the operating system for memory to hold things such as open files, images, or temporary calculations. Once it is done, the application is supposed to release that space so it can be reused. A memory leak occurs when the program loses track of some memory it no longer needs and never gives it back.
One forgotten allocation may be too small to notice. The trouble is repetition: if the application leaks memory each time it handles a request or opens an item, the unreleased pieces accumulate while the program runs. Restarting the application often clears them because its allocated memory can then be reclaimed.
Why the computer starts to stall
A computer has a limited amount of fast working memory, or RAM. As the leak consumes more of it, the operating system has less room for the programs and data currently in use. It may move less-used data to a storage drive to make room; retrieving that data later is much slower than reading it from RAM.
That shuffling can make ordinary actions lag. If memory pressure becomes severe, applications may stop responding, the operating system may struggle to keep essential work moving, and the computer can appear frozen. The machine has not necessarily run out of every kind of storage: it has run short of usable working memory and is spending too much time trying to manage what remains.
The delay is what makes leaks deceptive. A program can seem fine at first, then become increasingly sluggish after hours or days. Closing the offending application may restore responsiveness; a lasting fix requires correcting the program so it releases memory it no longer needs.
