What's the difference between a game freezing and crashing?

A crash terminates the game (the process ends and the window closes), usually from a fatal error, leaving a stack trace. A freeze means the game stops responding but keeps running, stuck rather than dead, usually because the main thread is blocked by a deadlock, infinite loop, or long operation. On mobile, a long freeze is often flagged by the OS as an ANR. They feel similar to players but have different causes and need different fixes.

How do I fix a game that freezes?

Find what's blocking the main thread, the deadlock, infinite loop, or long operation, and address it. Often the fix is moving heavy work (computation, file or network I/O, large asset loads) off the main thread so it can't block rendering and input, or fixing the logic causing a deadlock or infinite loop. Capturing context around when the game stops responding helps you pin down the blocking operation, since a freeze (unlike a crash) may not leave a clean stack trace.

What Causes a Game to Freeze?

Quick answer: A game freezes when it stops responding but keeps running, usually because the main thread is blocked: a deadlock, an infinite loop, or a long operation running where it shouldn't. It's stuck, not crashed.

A freeze, where the game stops responding but doesn't close, feels like a crash to players but has different causes. The game isn't dead; it's stuck. Understanding why points you at the fix. Here's what causes a game to freeze.

Why a Game Gets Stuck

A freeze means the game is running but not progressing, usually because the main thread (the one that updates and renders the game and handles input) is blocked. A few things block it.

Deadlocks, two parts of the code waiting on each other so neither can proceed
Infinite loops, code stuck repeating forever without exiting
Long operations on the main thread, heavy computation, slow file or network I/O run where it blocks everything else
Waiting forever on something, a resource, lock, or response that never comes
Synchronous loads, loading a large asset or level on the main thread, freezing the game until it finishes

In each case the main thread can't continue, so the game stops responding to input and appears frozen, even though the process is still alive.

How a Freeze Differs From a Crash

Unlike a crash, a freeze doesn't terminate the game, the window stays open, often with a frozen frame or spinning cursor. This difference matters for diagnosis: a crash leaves a clean stack trace at a failure point, but a freeze is the program stuck, not failed, so it may not produce one. On mobile, a long freeze is often surfaced by the OS as an ANR.

Because a freeze is the program stuck rather than failed, diagnosing it means finding what blocked the main thread, a different investigation than a crash. Bugnet captures crashes with stack traces and helps surface patterns in unresponsiveness.

Finding and Fixing the Cause

Fixing a freeze means finding what's blocking the main thread, the deadlock, infinite loop, or long operation, and addressing it, usually by fixing the logic or moving heavy work off the main thread so it can't block rendering and input. Capturing context around when the game stops responding helps pin it down.

Bugnet captures errors and context from real sessions, helping you spot the conditions around freezes. So a game freezes because its main thread is blocked, by a deadlock, infinite loop, or long operation, and the fix is finding and unblocking that thread, often by offloading the blocking work.

A game freezes when its main thread is blocked, by a deadlock, infinite loop, or long operation run where it shouldn't. It's stuck, not crashed. The fix is unblocking the thread, often by offloading heavy work.