.BAK is the previous version of the .PRG When you modify and save a .PRG, the old version is renamed with the .BAK extension.

.FXP is the compiled code of the .PRG It get generated when the .PRG is run or compiled.

You can safely delete the .BAK files. You can delete the .FXP files if you are running your application from the .APP or .EXE and the file is included in the project.

HTH

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>In my prgs folder there are my .prg files, .fxp files and .bak files. I use to know the answer to this question, but I no longer remember. What is the purpose of the .bak, .fxp and how are they created? Can I delete the .fxp and .bak files without causing any harm?