Mysterious V6 Slowdown

A few weeks ago I came across a very strange slowdown problem with V6. The customer informed me that it was taking at least five minutes to open quotes, big or small. I logged into the computer and checked the installation. It was a brand new Windows 7 machine and V6 had just been installed so everything was set up correctly.

So I started my usual checks. First was event viewer. I noticed some warnings in there regarding dynamically loaded dll’s. I hadn’t seen that event before and looked into it.

Using the fantastic Process Monitor from Microsoft’s SysInternals, I noticed in the stack of the V6 executable a dll that looked out of place. Checking the properties of this dll showed that it belonged to the anti-virus software installed on the machine.

I hoped that disabling the anti-virus would unload the dll. I was wrong. To dig deeper I loaded up Autoruns (also from Microsoft’s SysInternals) and noticed that the dll was listed in the AppInit section. Disabling this entry and restarting the system solved the problem!

I looked into what AppInit is. It’s a deprecated “feature” (if you could call it that) where dlls are loaded when user32.dll is loaded at startup. This knowledge base article and Microsoft’s Raymond Chen explain why this “feature” should not be used.

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