On Oct. 19, 2026, Windows Latest reported finding EmulateHeap listed in Compatibility Administrator on one Windows 11 26H2 PC. EmulateHeap is a compatibility fix that redirects an enabled process’s operating-system heap calls to replacement functions that imitate Windows 95 behavior. It gives older software a way to rely on memory-management behavior it may expect.
What the Windows 11 26H2 report found
Windows Latest’s reporter said the entry appeared in Compatibility Administrator on one PC. Microsoft’s September 2026 Windows ADK documentation lists Compatibility Administrator and support for Windows 11 26H2, 25H2 and 24H2. Windows Latest reported the one-PC listing, while Microsoft’s ADK documentation describes the toolkit and supported Windows versions.
To find the entry, Windows Latest’s reporter installed the ADK, selected Application Compatibility Tools and opened the 32-bit Compatibility Administrator. The reporter then used Custom Databases > New Database > Create New > Compatibility Mode and scrolled through the fixes list.
How EmulateHeap works
A heap is memory an application uses for allocations while it runs. When EmulateHeap is enabled for a process, it redirects operating-system heap functions to replacements that reproduce Windows 95’s heap behavior. Microsoft engineer Raymond Chen explains that the compatibility code was made by copying and recompiling the Windows 95 Heap Manager source, then adding it to Windows’ compatibility infrastructure. The old code loads and does its work for the process with the fix enabled, as Chen describes in his Microsoft Learn column.
Why older applications can depend on the old heap
Some legacy programs may rely on behavior that happened to hold on their original system. Chen gives examples: an application might expect a later allocation to reuse a particular memory address, or expect the contents of freed memory to remain the same or change in a certain way. These are accidental dependencies in the program, not evidence that Windows 95’s heap was generally better.
There is a tradeoff. Chen says newer low-fragmentation heap behavior must be turned off while EmulateHeap is enabled, because it could change the behavior an older application expects. EmulateHeap is therefore a targeted compatibility fix, not a general memory-management upgrade.
The SimCity workaround was separate
EmulateHeap is different from the Windows 95 workaround for SimCity. In an account published by Joel Spolsky, he attributes the game’s memory-bug explanation to Jon Ross, the original SimCity for Windows 3.x author: the game read memory after freeing it. Spolsky recounts that Windows 95 used a special allocator mode for SimCity that did not free memory immediately. Spolsky’s account describes that game-specific workaround; EmulateHeap reproduces Windows 95 heap behavior for a process when the compatibility fix is enabled.
A 2023 user report described problems on Windows 11 22H2
On March 15, 2023, an anonymous user on Microsoft Q&A reported problems after enabling EmulateHeap or Windows 95/98/ME compatibility modes on Windows 11 22H2. The user reported sound loss in Grand Theft Auto: Vice City and Grand Theft Auto III; crashes in Grand Theft Auto: San Andreas, Need for Speed: Most Wanted 2005 and InstallShield programs; and hangs in Thief II and Thief 1 Gold Edition. The post records that user’s account.
