after updating to Texmaker 4.0.4 today, I am no longer able to compile my PDFs more than once per Texmaker session. I need to quit Texmaker and run it again to compile again. The error I get is the same, as when you try to compile, but have the file opened in Adobe Reader for example.
I am using the internal PDF-viewer and have not changed any Texmaker settings. To compile my work I use the quick build feature set to run pdflatex and view pdf.
I did not have this problem before.