Newly occurring error sound

On my Windows 8.1 machine I'm newly hearing asound over the computer speakers when a specific group of files are being transferred. The sound is a series of 10-15 fast beeps run together followed by one Windows error chime. The log indicates no errors or failed transfers.

Every night I run this batch file:
The sounds always happen while files are being synchronized from one particular folder that contains subfolders. When I run the batch file manually and watch the files streaming down in the command prompt window, I notice the stream slows down just before I start hearing these beeps. What are these sounds indicating and why would they be showing up just recently after years of quiet transfers? THANKS.

I do not think it's WinSCP that does that. I'm quite sure that WinSCP does not play any sounds ever in the scripting mode.

Thanks. Because the script transfers scores of folders, I created a test script that transfers the seven folders (and subfolders) where the sound occurs. Again, I see no errors in the log, but there is a folder named Antique Radio Forums • View topic.

I seem to remember something about WinSCP and long file names and/or special characters. Would the special characters cause sounds to chime?

Ok, it might be that Windows console beeps when WinSCP tries to print some special/wrong characters. If you want to resolve the problem with the stray folder, please post log file.

Thanks. My workaround to keep this from waking me up at night was to simply exclude the folder from the sync. These are files that I rarely change or update, so that's acceptable for now. Practically speaking, my issue is resolved, although I remain curious why, after years of quiet transfers, these beeps would suddenly appear.

If it would be of interest to others, I'll run a sync of just that directory and post the log. I'll wait to do that after I see if someone wants it.

Thanks for your help. Keep up the good work!