How to Detect and Troubleshoot Resource Memory Leaks in Unity
As Unity, hardware, and production standards evolve, GameOptim continues to refine its performance optimization methods and share practical guidance with developers. Resource memory leaks are among the most common and difficult issues to diagnose because their impact may remain hidden until a game has been running for hours.
This guide explains how to identify potential resource leaks using GOT Online, interpret resource lifetime data, and compare resource usage across scenes and frames. It also covers why short test sessions may miss long-term memory issues and how to build more effective testing workflows.
Summary Monitor resource usage trends: Continuously increasing resource memory usage may indicate resources are not being released properly. Inspect resource lifetimes: Use GOT Online to identify resources that remain in memory and determine whether they are intentionally preloaded or potentially leaked. Compare scenes and frames: Examine different resources in similar scenes and shared resources across different scenes to narrow down potential leaks. Run longer test sessions: Short tests lasting 10–15 minutes may not reveal memory leaks that emerge after several hours of gameplay. Why Are Unity Resource Memory Leaks So Difficult to Diagnose? Memory leaks are among the most common and frustrating issues developers encounter during game optimization. The main challenge is that, before identifying the source of a leak, it is difficult to predict how much memory will accumulate or when the problem will become noticeable in a live environment. For example, some developers have reported that their games run normally for the first 30 minutes, but become increasingly laggy after three to four hours of gameplay. This behavior can be unexpected if the team has not tested the game over sufficiently long sessions. So, how can developers identify and troubleshoot these issues before they affect players? How to Identify Potential Resource Memory Leaks with GOT Online In GOT Online, the Assets report provides resource usage trends over time. Pay particular attention to patterns in which resource memory usage continues to increase rather than stabilizing. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/680ed7d2 c37c 4f5b a626 e9f9b3f56c64.png Another warning pattern is a series of increasingly high peaks, where resource usage keeps climbing instead of returning to a stable level. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/2b15cbfa 6d52 4079 bab8 13174b2b2d9c.png One likely cause is that the development team caches resources after loading them, such as by storing references in a , but fails to remove those references or clear the cache when switching scenes. As a result, the resources may remain referenced and cannot be released through the engine's normal cleanup process. Even manually calling APIs such as may not unload resources that are still referenced by the cache. This can lead to persistent resource retention and potential memory leaks. The following workflow explains how to investigate these issues more systematically. 1. Track the Lifecycle of Each Resource Understanding a resource's lifecycle means knowing where and when it is used throughout the game's runtime. In GOT Online, open the Resource Details page to inspect resource information collected during gameplay. Select a specific resource to view its lifecycle timeline, including the scenes in which it was loaded and unloaded. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/4b6de687 4847 46d0 8d3d 52ecc8f222c0.png This feature helps developers quickly identify resources that remain in memory throughout gameplay and determine whether they are intentionally preloaded or potentially leaked. Loading screens and login screens are common examples. Their images can consume a considerable amount of memory, so keeping them resident throughout the entire session may be unnecessary. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/0f0856ad ba0b 491a b0d5 86ce4bc4b6e3.png Review whether these resources are genuinely needed after the corresponding screens have been left. If not, investigate why they remain loaded and whether their references or caches are being released correctly. 2. Compare Resource Usage Across Scenes and Frames A Unity project can contain hundreds or even thousands of resources. Inspecting every resource individually is rarely an efficient way to identify a leak. Instead, compare resource usage across scenes and frames. The goal is to narrow down the list of suspicious resources by checking whether their presence is consistent with the expected behavior of the game. Method 1: Compare the Same Scene or Similar Scenes Focus on resources that differ. Resource usage is generally relatively consistent across repeated visits to the same scene or across scenes of the same type. Compare resource snapshots from different points in time, focusing on resources that appear in one snapshot but not the other. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/e2c9880b 325e 4e79 bfb2 0ba2625a6257.png For each resource that differs, ask whether its presence is expected. For example, if a resource remains loaded after leaving a scene and returning to it multiple times, even though the resource should no longer be needed, investigate whether its references are being retained unintentionally. By checking the expected lifecycle of these different resources, developers can quickly narrow down potential leaks and identify the resources involved. Method 2: Compare Different Types of Scenes Focus on shared resources. Different types of scenes generally use different sets of resources, apart from resources intentionally kept in memory across scenes. Compare the resources shared by two different scene types, then determine whether each shared resource is supposed to remain loaded. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/482f6dc2 38b5 4a4d 9612 b980c574828c.png If a resource is shared across scenes, that alone does not mean it is leaking. It may be a legitimate persistent resource. However, if the resource is not intended to remain resident and no longer serves a purpose in either scene, its continued presence warrants further investigation. This comparison helps distinguish intentionally persistent resources from resources that may be retained because of incorrect cache management or unreleased references. Method 3: Compare Different Frames Focus on whether shared and different resources are expected. You can also compare resource information between different frames to examine both shared resources and resources that appear only in one frame. https://uwa overseas public.oss us east 1.aliyuncs.com/uploads/markdown/0ec004e3 46ed 4135 862b 0e9f762a43d4.png Check whether the shared resources should remain loaded and whether the resources that differ match the expected behavior at each point in gameplay. By combining frame comparisons with scene comparisons and lifecycle timelines, developers can narrow down potential leak sources more efficiently. Once the investigation identifies the relevant resources and the cause of their continued retention, the underlying issue can often be addressed much more quickly. 3. Use Longer Test Sessions to Catch Delayed Memory Issues Beyond profiling and resource comparisons, we recommend maintaining test cases that run for extended periods. Many development teams run a game for only 10–15 minutes because shorter tests are more convenient. However, these sessions may not be long enough to expose memory leaks that accumulate gradually. Testing should reproduce realistic player behavior as closely as possible. During the optimization phase, include longer gameplay sessions, repeated scene transitions, and other scenarios that may expose resources that are not released correctly. A game that performs well during the first few minutes may still develop memory pressure after several hours. Sufficiently long tests help teams identify these issues before they affect players in production. FAQ How can I tell whether increasing resource memory usage indicates a leak? A continuously rising resource usage trend or progressively higher peaks can indicate that resources are accumulating instead of being released. However, these patterns alone do not confirm a leak. Check resource lifetimes, scene transitions, references, and expected caching behavior before drawing a conclusion. Why doesn't release some resources? Resources that are still referenced may not qualify as unused. If your project stores references in a cache or container and does not clear them when they are no longer needed, calling may not release those resources. What is the difference between a preloaded resource and a leaked resource? A preloaded resource is intentionally loaded and retained to support expected gameplay behavior or reduce loading delays. A leaked resource remains in memory unintentionally after it is no longer needed. The key is to compare its actual lifecycle with the intended resource management design. Is a 10–15 minute test sufficient to identify resource memory leaks? Not necessarily. Some leaks accumulate slowly and may only become noticeable after several hours. Longer test sessions that reproduce realistic gameplay are important for detecting delayed memory issues. About GameOptim GameOptim provides performance profiling and analysis solutions for Unity game developers, helping teams investigate performance bottlenecks and make data informed optimization decisions. GOT Online is GameOptim's cloud based performance analysis service. Upload profiling data from your local tests to review visualized performance metrics, resource usage trends, and detailed analysis reports. GOT Online provides several analysis modes: Overall Performance Analysis Mono Heap Memory Analysis Lua Performance Analysis GPU Performance Analysis Limited time offer: New users who successfully register receive 2 hours of free GOT Online testing time . Register to start investigating your Unity game's performance issues with GOT Online. https://www.gameoptim.com/?fopt=blog