## LaTeX forum ⇒ General ⇒ Package incompatibility? Topic is solved

LaTeX specific issues not fitting into one of the other forums of this category.
LarsWa
Posts: 5
Joined: Fri Nov 07, 2014 12:36 am

### Package incompatibility?

I have a 500 p textbook in LaTeX that I wrote a year ago. After migrating to a new computer (Win 7) I get the error message "!You can't use a prefix with '\begingroup'" on a line \Newassociation{hint}{Hint}{hint} related to the package Answers. When I created the minimal working example below, the error instead showed up at a later - but similar line - \Newassociation{solt}{SolutionTeacher}{solt}. The error seems to be related to what is discussed on tex.stackexchange.com/questions/112706/chemfig-package-compatibility: an incompatibility between different packages. In the stackexchange-post it was recommended to change the order of the different \usepackage-commands, but that does not help in my case. However, I still have a feeling that my problem is related to package incompatibility, as I do not get the error when I only use the Answers package; nor do I get it when I use the Answers package together with some other packages. The minimal problem seems to be a combination of the four un-commented packages below (answers, mchem, pdfpages, siunitx; found by trial and error).


BlackForestrian

Stefan Kottwitz
Posts: 9568
Joined: Mon Mar 10, 2008 9:44 pm
Hi Lars,

welcome to the forum!

Can you please post the .log file as attachment here? It would be good if you would add the command \listfiles to your preamble, so the log file would list the package names and versions in addition.

Stefan

Stefan Kottwitz
Posts: 9568
Joined: Mon Mar 10, 2008 9:44 pm
For information, the problem has been solved (cross-post site, link above).

It's caused by a bug which is not present in the newest LaTeX version, so an update would help. A workaround is defining a new dummy counter right before the line where the error happened, as egreg suggested.

Stefan