I have been running a program with Wine for over a year. With its version 3 there has been basically no problem. Lately, the program is upgraded to version 4 and it crashes with Wine. I tried to print out debug messages but can't seem to get any clue about what is wrong. While I was testing with the debug messages, an interesting thing I found is that if I run it with the following debug setting, it runs. Code: WINEDEBUG=relay wine program.exe >& test.log I found that the program has 2 processes running (same as version 3) -- one main program and one data server. I am guessing the comms between the 2 processes in version 4 have some syncing problem. With WINEDEBUG=relay, Wine writes a lot of data to disk, so one process is delayed and somehow helps with the syncing. How suggestion on how to get it to run or how to test it further?