VB Call to Shell Stops Working - PC Experts Help Needed

[BobLfoot]

I have an application call it PROGRAM_A which is a compiled exe from Visual Basic. 

PROGRAM_A's job is to build an output.txt file in the C:\Temp Folder and when built shell call PROGRAM_B. 

PROGRAM_B is also a compiled exe from Visual Basic. 

PROGRAM_B's job is to copy output.txt from C:\Temp to NetworkFolder_1 and NetworkFolder_2 and then delete the C:\Temp copy of output.txt.  

This setup of PROGRAM_A & PROGRAM_B has been running on several Windows XP SP3 PCs for over five years flawlessly.

Recently the setup of PROGRAM_A & PROGRAM_B stopped working.

PROGRAM_A still builds the files like it always has.

PROGRAM_B is called from the command line or by mouse double click from File Explorer does it's copy job just fine.

PROGRAM_A's shell call of PROGRAM_B apparently is not successful, but I see no error messages or log entries to suggest why it failed.

Neither PROGRAM_A or PROGRAM_B has been changed.

IT Dept. swears no new policies or patches were deployed to these machines.

I need suggestions as to where to look and how to diagnose this issue.

Unfortunately due to confidentiality I cannot share the source to PROGRAM_A or PROGRAM_B.

[Joe E.]

Only thing I can think of would be an OS update of some kind that only just now got installed. It's a real long shot since XP has been out of support for so long, but it may be possible. I know our IT department manages all Windows Updates, so it may be an update thing that was delayed or something rather than a policy or patch specifically. Does the Windows system log show any updates? It *shouldn't*, but we all know better than to trust that, right?

Could possibly also be a secret update to a firewall or something.

Maybe I'm overly cynical, but I've seen problems traced back to IT updates that IT swore never happened...but did.

[panic mode]

i agree... if things used to work, the only reason they stop working is when something external changes. few months ago i run into issue that one of my application started experiencing odd things from time to time. look into event logs confirmed that it coincided with IT script that was executed every hour and included command that was applying group policy update. rewrote TCP server that was affected and life was good again.

back to this issue....are there more details to the programs? what kind of visual basic? VB5/VB6? or VB.NET? 

you may not share the code but since you have access to it, you can step through and see what happens. add try/catch and display message. or just google for suitable example to replace part of code that does call of program B. there are different ways to do this but usually it is either shell command or process start.

if needed to get hands on development environment just create VM and install older Windows and VB. all of this can be downloaded from Archive.org (and i did the same just recently since needed to develop/test for Win2k). needed product keys are there as well since such products have been long retired.

[panic mode]

btw, there may be no need to call program B from program A. as long as file is created and saved in right location, program B could simply watch the folder for changes and when file is there, copy it to target locations. this is very simple function to create. 

[panic mode]

here is a little thingy that may do the trick of give you ideas https://forums.mrplc.com/index.php?/files/file/1171-simple-backup-utility/