FIX: Only One Browser Helper Object Will Load with Internet Explorer 5 (229970)

SYMPTOMS

Only a single Browser Helper Object (BHO) registered will load with Internet Explorer 5.0. Subsequent loads of other registered BHOs fail without apparent error.

CAUSE

With Internet Explorer 4.x, multiple BHOs can be registered under the following key, and all of them will load when you start Internet Explorer:

HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects

Under Internet Explorer 5.0, multiple BHOs can be registered, but only a single one will be loaded, because of an internal buffer problem.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article. This problem was corrected in Microsoft Internet Explorer version 5.01.

MORE INFORMATION

Internet Explorer uses RegEnumKeyEx to enumerate through the BHOs registered under the key mentioned above. Only the first BHO returned during this enumeration will be loaded.

Depending on whether the operating system is Windows 95 and Windows 98 or Windows NT, the BHO that is loaded may be different. On Windows NT, the BHO with the lowest CLSID will be loaded. On Windows 95 and Windows 98, the BHO that was the first registered will be loaded.