>The project manager appears to use it (along with the timestamp field) to determine if a source file has changed so it can recompile it. The problem is that the project manager often gets confused and recompiles forms/classes even if they haven't changed which can play havoc with a source control system (during a DST change, for example, but there are other circumstances as well). It seems to be more profound with large projects like ours. I'd like to be able to "trick" the project manager into thinking that the current version of a source file matches the timestamp and checksum in the project so it won't recompile it.
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>I can update the 32-bit timestamp in the project file to match the source file, but the CKVAL field seems to signal the project manager that the source file has changed.
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>Do you know how it's calculated?

No I don't but it definitely is related to the values stored in the Symbols field.