The j5 IndustraForm Designer log files are displayed in the bottom bar of the Designer.
To view more of the recent log files, select Logs 
in the bottom right corner of the Designer.
The j5 IndustraForm Designer's log files are stored in the following location:
C:\Users\<USER>\AppData\Local\j5\j5-ide\log
The j5 IDE log files are also stored in this location.
The logs are separated by day, and by different running instances of the Designer. The file naming convention is: logfile-YYYYMMDD-n.log - where "n" is the count of the different running instances of the Designer.
The j5-IFD-crashlog.log files are also in this folder. These files contain the crash information of the Designer going back several months. A traceback and a Windows exception code is included in these logs.