This article lists some limitations in 64-bit Windows.
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No Mixed 64-Bit/32-Bit Processes
| • | 64-bit programs cannot load and call 32-bit MDAC. |
| • | 64-bit Microsoft Internet Explorer cannot load 32-bit ActiveX controls. |
| • | The 64-bit shell cannot load 32-bit Inproc shell extensions. |
| • | 32-bit installer programs cannot load and register 64-bit DLLs. |
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No 16-Bit Code
| • | No 16-bit code can run, except for recognized InstallShield and Acme installers (these are hard-coded in Wow64 to allow them to work). |
| • | 16-bit Setup bootstraps are not supported. |
| • | 16-bit MS-DOS and Microsoft Windows 3.x utilities will not start. If you attempt to start such a program, you receive a "Program.exe is not a valid Win32 application" error message. |
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No OS/2 or Posix Program Support
There is no support for OS/2 or Posix programs.
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No Kernel-Mode 32-Bit Code
There is no support for Kernel-mode or 32-bit code such as:
| • | 32-bit virus-detection or 32-bit file system filters. |
| • | 32-bit video adapter or 32-bit network adapter drivers. |
| • | 32-bit Kernel-mode printer drivers. |
The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, regarding the performance or reliability of these products.
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