Hi,
This error occurs if I select Debug and Debug:Serial, despite the exact same project building OK in Release mode, as well as for hardware debugging.

The missing directory is, in fact, missing, but the parent is there and has several files and directories in it.

AFAIK, the error occurs on the first library, and occurs for cloned and uncloned libraries.

EDIT:  I should have said this has been happening for a long time, not just the most recent update - just got round to reporting it.

Simon,
That did not help, same result.

Built a simpler example.  I started a new solution, with only the Arduino project, with Deep Search - built fine.

Tried again, with Deep search OFF and the library included as a shared project, cleaned solution - failed as I described.

Same if the library is cloned for the solution.

Unloaded the library project, removed reference, cleaned solution, built OK again 

I will email you the output, SLN and VCXPROj files.

Attached

Thanks for the response.

I would be lying if I said I understood all that, or if I claimed to know anything about VS configuration files, but are you referring to the existence of two entries for TaskClass.vcxitems in the .sln file, with the same path but different GUIDs?  One of the GUIDs matches the cloned TaskClass.vcxitems, the other is a mystery, as there can be only one file with the name in that folder.  Maybe a red herring.

As an experiment, I created an empty sketch using the VM template and an empty library also using a VM template, and cloned the library into the sketch solution.  There were again two entries in the .sln for the library vcxitems, so that's probably nothing to do with it.   

For this empty solution, the same "folder does not exist" message occurred during a Debug:Serial build, but as I said before, it builds fine for Release and for Debug:Hardware.  Given that, I can't see how it is anything to do with solution organization.

Regarding that, the layout you gave is what I generally use, cloning for the solution if I need to modify a stock library, or if I want to freeze the whole state of the build, even if there is only one sketch/project using the library. Otherwise, I'd probably make it an uncloned shared project so I can more easily browse it if needed.

I'll attach a screenshot of my solution organization.

Then there is definitely something I am not getting. 

Firstly, that is where the IDE put it when I selected Clone to Solution.  Might be expected to be correct.

Secondly, if I moved Libraries up a level, it would conflict with the standard Arduino Sketchbook\libraries folder and would overwrite itself?

I tried moving the sketch down a level (actually two, since the sketch has to be in a directory of the same name) to get the attached screenshot, but it was just the same error.

So I don't get what the recommended way to organize the solution is, or how it is going to help this issue in any case - since it only becomes evident on Debug:Serial builds.

Can you reproduce the error if you follow the simple sequence I outlined in my last post?

Tim,
Cleaning solution does not help.  Obviously I've tried that many times.  I do get an error when I clean the solution, which looks harmless, but I will attach it, as well as the build output.

As for VM and shared projects, I have been using VM for close to 10 years and shared code/libraries for about 4 or 5, so while I cannot claim any great knowledge of the internals (just a user), I have managed to successfully develop three large solutions, with multiple projects and lots of shared code and cloned libraries, and the only issue I have that I cannot blame on myself is this build failure in the very specific situation of a cloned library in debug configuration, but only with the Serial debugger enabled.  For all solutions, from the trivial to pretty large.  For ESP32, Uno and ATMega2560 at least.  And it's been going on for quite a while.  I just tested with VS 2019 (VM version 1.2022.0607), and get the same result.

So, you did not respond to my earlier question: can you reproduce this error?  I think that has to be the first question.

Sent you email

Simon,
Thanks, that does seem to eliminate the error.

I was having the same issue.  This fixed it, thanks!