Help for fixing the 'Runtime error 200 at ...' error

Symptom: A legacy MS-DOS program crashed while leaving the cryptic error message.

Runtime error 200

Runtime error 200 in DOS.

A runtime error 200 message usually occurs with old DOS applications written in Turbo and Borland Pascal. Turbo Pascal had a timing bug that would cause its complied programs to crash when they were operating on machines running at 200Mhz or faster. It is known as the CRT unit issue and can be fixed by applying a patch to the effected application. Otherwise you can run the application in DOSBox which can artificially slow down the speed of the emulated DOS session.

If you wish to patch the application we have created a guide to help you through it. Though this is only recommended for people experienced with DOS or the Windows command prompt.

1. Download UNP 4.11 which is a Turbo Pascal decompression program.
2. Download CRTFix 1.16 which as its name says is a CRT bug patching program.
3. Create a temporary directory.
   MKDIR C:\TPPATCH
4. Unzip both downloaded packages into the temporary directory.
5. Copy the application effected by the CRT issue into the temporary directory.
6. In our example we are going to patch defacto.exe which is part of an early Defacto magazine program.
7. Now run the UNP program to decompress the application.
   UNP DEFACTO2.EXE
8. Once the decompression is complete run the crtfix program to patch the application.
   CRTFIX DEFACTO2.EXE

Step 3. Our temporary directory.

Step 7. Running the UNP program.

Step 8. Running the CRTFIX program