Check one of the failing workstations and note all available information abotu the KiXtart executable like version, file size, date stamp, and so on. then compare with the original source on your distribution servers to find out what's different. Then do a binary compare if everything else is identical to see whether there have been some bytes changed. Finally, check the KiXtart executable with two separate antivirus scanners to make sure it's not infected.
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There are two types of vessels, submarines and targets.