Content Manager issue?

I’ve been working on a little app of sorts to generate a few bits of text. It actually just draws random values from dictionaries and prints them on the screen (it’s for a school project). I opted to do it in Monogame because I’m familiarized with it and would like to have background images, etc.

Anyway, I was doing this on the WP also, and had no issues there. However, on the PC, I changed the background image for another one with the same name and, since, all I get is this:

An unhandled exception of type 'System.ArgumentNullException' occurred in mscorlib.dll Additional information: Valor não pode ser nulo.(Value can't be null)

It doesn’t point out anything in the code, just shows this on a blank screen of sorts.

After a while I gave up and started a new Windows project, in which I just pasted the code from earlier, added the images back and it worked flawlessly. According to a friend of mine, this might be a Monogame issue, though I don’t remember ever getting this before. Also, as I’ve stated, the same code works if I put it in a new project or run it on the Windows Phone.

Any tips on what I could be doing wrong? Or is it something on the framework’s side?

Without some sample code or the assets in question, it’s difficult to make a guess what could have been the cause.

Is this the error message in the console or the stacktrace from a trycatch? (I suspect the 1st)
You dont always have the stacktrace in the console when an exception is triggered (depends on the library used)

Are you seeing this in the pipeline tool, or in your Solution.

One thing to try is to make a copy of your content project and add/remove items and rebuild it. Once you find out which asset is causing the problem, you will have a better idea as to what is going on.