我的安装程序有 32 位和 64 位版本，它们具有（几乎）完全相同的代码和自定义操作序列（只有与此问题无关的微小差异）
我希望我的安装程序检测它之前是否已经安装过，在这种情况下运行我自己的代码而不是显示默认的 Windows Installer 错误：
该产品的另一个版本已安装。此版本的安装无法继续。要配置或删除本产品的现有版本，请使用控制面板上的添加/删除程序。
我的 32 位安装程序工作得非常好，如果我在产品已安装时运行安装程序，它会运行我的自定义代码，但我的 64 位安装程序中的相同代码和自定义操作无法正常工作，并且总是显示不需要的错误味精。
CheckPreviousVersion 是在 UI 序列中作为自定义操作调用的第一个函数，我尝试将它放在不同的位置，例如在 InstallValidate 之后，但没有任何效果。
我检查了详细的日志文件，但找不到任何可以解释这种行为的东西，这是日志的一部分：
=== Verbose logging started: 05/03/2013 16:27:20 Build type: SHIP UNICODE 5.00.7601.00 Calling process: C:\Windows\system32\msiexec.exe
===
MSI (c) (0C:94) [16:27:20:331]: Machine policy value 'Debug' is 0 MSI (c) (0C:94) [16:27:20:331]: ******* RunEngine:
******* Product: foo.msi
******* Action:
******* CommandLine: ********** MSI (c) (0C:94) [16:27:21:546]: Machine policy value 'DisableUserInstalls' is 0 MSI (c) (0C:94) [16:27:21:557]: SOFTWARE RESTRICTION POLICY: Verifying package --> 'C:\Builds\.msi' against software restriction policy MSI (c) (0C:94) [16:27:21:557]: Note: 1: 2262 2: DigitalSignature 3:
-2147287038 MSI (c) (0C:94) [16:27:21:557]: SOFTWARE RESTRICTION POLICY: C:\Builds\.msi is not digitally signed MSI (c) (0C:94) [16:27:21:558]: SOFTWARE RESTRICTION POLICY: C:\Builds.msi is permitted to run at the 'unrestricted' authorization level. MSI (c) (0C:94) [16:27:21:584]: Cloaking enabled. MSI (c) (0C:94) [16:27:21:584]: Attempting to enable all disabled privileges before calling Install on Server MSI (c) (0C:94) [16:27:21:586]: End dialog not enabled MSI (c) (0C:94) [16:27:21:586]: Original package ==> C:\Builds\....msi MSI (c) (0C:94) [16:27:21:586]: Package we're running from ==> C:\Builds\.....msi MSI (c) (0C:94) [16:27:21:589]: APPCOMPAT: Uninstall Flags override found. MSI (c) (0C:94) [16:27:21:589]: APPCOMPAT: Uninstall VersionNT override found. MSI (c) (0C:94) [16:27:21:589]: APPCOMPAT: Uninstall ServicePackLevel override found. MSI (c) (0C:94) [16:27:21:589]: APPCOMPAT: looking for appcompat database entry with ProductCode '{B8CBA92E-2140-48AB-B4EA-A4C3FF10295B}'. MSI (c) (0C:94) [16:27:21:589]: APPCOMPAT: no matching ProductCode found in database. MSI (c) (0C:94) [16:27:21:599]: MSCOREE not loaded loading copy from system32 MSI (c) (0C:94) [16:27:21:608]: Machine policy value 'DisablePatch' is 0 MSI (c) (0C:94) [16:27:21:608]: Machine policy value 'AllowLockdownPatch' is 0 MSI (c) (0C:94) [16:27:21:608]: Machine policy value 'DisableLUAPatching' is 0 MSI (c) (0C:94) [16:27:21:608]: Machine policy value 'DisableFlyWeightPatching' is 0 MSI (c) (0C:94) [16:27:21:609]: APPCOMPAT: looking for appcompat database entry with ProductCode '{}'. MSI (c) (0C:94) [16:27:21:609]: APPCOMPAT: no matching ProductCode found in database. MSI (c) (0C:94) [16:27:21:609]: Transforms are not secure. MSI (c) (0C:94) [16:27:21:609]: PROPERTY CHANGE: Adding MsiLogFileLocation property. Its value is 'C:\Builds\Angoss\Products\Workstation\single-exec\INSTALL64.LOG'. MSI (c) (0C:94) [16:27:21:609]: Command Line: CURRENTDIRECTORY=C:\Builds\Angoss\Products\Workstation\single-exec CLIENTUILEVEL=0 CLIENTPROCESSID=7948 MSI (c) (0C:94) [16:27:21:609]: PROPERTY CHANGE: Adding PackageCode property. Its value is '{}'. MSI (c) (0C:94) [16:27:21:609]: Product Code passed to Engine.Initialize: '' MSI (c) (0C:94) [16:27:21:609]: Product Code from property table before transforms: '{}' MSI (c) (0C:94) [16:27:21:609]: Product Code from property table after transforms: '{}' MSI (c) (0C:94) [16:27:21:609]: Product registered: entering maintenance mode MSI (c) (0C:94) [16:27:21:609]: Determined that existing product (either this product or the product being upgraded with a patch) is installed per-machine. MSI (c) (0C:94) [16:27:21:609]: PROPERTY CHANGE: Adding ProductState property. Its value is '5'. MSI (c) (0C:94) [16:27:21:609]: PROPERTY CHANGE: Adding ProductToBeRegistered property. Its value is '1'. MSI (c) (0C:94) [16:27:21:609]: Entering CMsiConfigurationManager::SetLastUsedSource. MSI (c) (0C:94) [16:27:21:609]: Specifed source is already in a list. MSI (c) (0C:94) [16:27:21:609]: User policy value 'SearchOrder' is 'nmu' MSI (c) (0C:94) [16:27:21:609]: Machine policy value 'DisableBrowse' is 0 MSI (c) (0C:94) [16:27:21:609]: Machine policy value 'AllowLockdownBrowse' is 0 MSI (c) (0C:94) [16:27:21:609]: Adding new sources is allowed. MSI (c) (0C:94) [16:27:21:609]: PROPERTY CHANGE: Adding PackagecodeChanging property. Its value is '1'. Another version of this product is already installed. Installation of this version cannot continue. To configure or remove the existing version of this product, use Add/Remove Programs on the Control Panel.