Hi David,
that cryptic error message comes back from GDB, and I agree, it is not every helpful. I think this is one of the biggest complains about GDB, but changing GDB unfortunately is not the topic here. Understanding how GDB works can help:
What is causing such an error message is usually some bad arguments or failure of launching the GDB server from the client in Eclipse (see https://mcuoneclipse.com/2015/05/18/gdb-client-and-server-unlocking-gdb/ about that concept). The same article describes one reason and solution for the "error in services launch sequence", so you might check that one. The same message you get if the GDB server cannot be found (I have seen cases where firewall software has removed it because it communicates through TCP/IP), so you should check if the server is still present on your machine.
If that does not help, it would be helpful for me if you could post here your launch configuration files (or screenshots of it), as I think some settings might be wrong. What should work is if you create a new project with File > New > Processor Expert project (you don't need to turn on Processor Expert), as this creates a simple project with working launch configuration settings). If that fails too, then it is not a problem of your project files, it is very likely a problem with the GDB server on your disk, or a problem with your OpenSDA firmware or drivers.
I hope this helps,
Erich
PS: Not sure which designer you mean? I'm using internet search engines (google for example) to help me out. There is as well a compendium (https://mcuoneclipse.com/compendium/ ) in an attempt to structure the information. If you have any suggestion how to improve it, please let me know.
