You definately want to use the MTDLL if running under MTS. You use it just like the Single threaded DLL...in other words, don't do anything different. MTS handles the threading. Multithreaded is misleading. The DLL is really Apartment Model threaded. If you use the Single threaded, then subsequent calls will be blocked, slowing down your application.

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>We have the runtime libraries in the same directory as our DLL.
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>I'm not sure how we would find registry entries relating to the DLL - do we just search on the name of the DLL and the name of the class ?
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>I'll take your advice re. using MTDLL, but how do we use it under MTS ? Is MTS a standard component of a Windows NT installation ? Also, the single threaded DLL appears to work ok on our test NT and 2000 servers - we have even tested on a freshly installed server with no problems.
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>Best.
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>Matt.