Documentation highlights that Protel 99 SE may require specific to function correctly. If new software updates these drivers, it can cause errors, often solved by a full reinstallation of Protel to restore its local copies.
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Protel 99SE PCB Design Tutorial | PDF | Printed Circuit Board - Scribd Documentation highlights that Protel 99 SE may require
This IS the Patch for Protel99se SP6 for Win7/8/10. - EEVblog it can cause errors