I'm using VSMicro in VS2019 with the serial debugger. Everything works fine before I start debugging for the first time. I can add breakpoints and/or tracepoints as expected. But after I end the debugging session (by clicking the "Stop" icon in the toolbar) I can no longer edit the breakpoints. All fields in the breakpoint properties (trace message, conditions) are grayed out and cannot be changed. This applies to existing breakpoints as well as new ones and is 100% reproducible.

Additionally, VS becomes partially unresponsive after this happens, e.g. files newly opened in the editor just open a black, empty window. The only solution is to restart Visual Studio after each debugging session.

The problem has been there since at least a year, but I only used VSMicro occassionally as debugger so far. Version currently used is 2021.1108.1904.

@Simon I have attached the build output, but I don't think the problem is related to any build setting, because it happens irrespectively of any setting I see or the toolchain. The example is from an ESP32, but it happens for all boards I used (tested Arduino Uno and Arduino Due). 

My suspicion is that it has something to do with culture settings or maybe the fact that I'm using a german version of Visual Studio.

Yes, the language pack for "English (United States)" is installed. However, I'm using "German (Switzerland)" as my culture.

Hey, wow! That really appears to have solved the issue. Great you were able to track this one down despite my quite vague assumption. I will need some more testing to finally confirm that everything now works as it should.