Posted 2 Oct 2021 (edited) I am trying to online edit a program in a MELSEC QCPU, using GX Works2, but I keep getting this error "A file which does not exist in the PLC was specified" <ES:010a4022> Few weeks ago I had just online edited the same program in the same PLC with the same steps with no problem. There had been no changes to the PLC after that. Just all a sudden when I try to edit yesterday I get this error. Not an expert in Mitsubishi, just started learning the basics. Connection to PLC is by USB cable. Steps I followed to connect to PLC: -Online > Read from PLC -Select PLC Series: QCPU (Q mode) -Select PLC side I/F Serial Setting: Serial USB -Select all target program to Read, then Execute I am editing the file that I had just read from PLC Steps I followed to online edit: -Online > Monitor > Monitor (Write mode) -Execute the function below when mode is changed: Checked all -Edit the program (basically just deleted one -||- contact and drew back the line) -Compile > Online Program Change Then Bam! error get! "A file which does not exist in the PLC was specified" <ES:010a4022> I had tried Verify with PLC, but all results match. Is there something I am missing? Help much appreciated! Edited 2 Oct 2021 by QHJ Font issues :p Share this post Link to post Share on other sites