The residual information plotted to the screen are stored temporarily during the run in a file called “mon”. If you look in the temporary run directory (.dir) while the solver is running you’ll see this file. After the run, the information in this file is imported into the res file and the mon file disappears. What can happen to cause the error is that, during run when the data is being written to the mon file or when the mon file info is transferred to the res file after the run, an error is occurring in the write process to corrupt the file at a certain line. This can happen if you’re solving and writing over the network and there’s some temporary issue in the data transmission over the network. Some ways to fix the problem: 1.) When you restart the model, don’t use the “continue history from” option. This will then use the previous results to initialize the model but will start the residual history from that point. 2.) It’s possible to extract the mon file data from the res file to a .csv file, try to repair it, then read the exported .csv file back into the res file. To do this, use the cfx5mondata command executed from the command line (see 1.2.3.5. Exporting Monitor Data from the Command Line in the CFX Solver Manager guide). Repairing the mon file might be a little tricky. Usually, it’s typically two lines of data got merged together at some location and it’s possible to fix it. However, it may not be worth the effort.