# Problem when compiling presentation

Preparing my presentation, everything was going well until one time when compiling I got the following error:

(beamer.cls
("C:\Program Files\MiKTeX 2.9\tex\latex\beamer\base\beamerbasercs.sty")
! Undefined control sequence.
<argument> \beamer@rcsdate \space \beamer@version
\space A class for typeset...
l.14 ...ace A class for typesetting presentations]

?

Process has been terminated ...


I don't understand what this means. Can someone help me please.

• Welcome to TeX.SX! This seems a problem due to a faulty installation of MiKTeX. You should avoid using file names with spaces anyway. – egreg Jan 17 '16 at 11:12
• Dear egreg, the same problem persists, nothing new – user96111 Jan 17 '16 at 11:17

(beamer.cls
("C:\Program Files\MiKTeX 2.9\tex\latex\beamer\base\beamerbasercs.sty")


That is, you have a beamer.cls in the current folder but are then including beamer internals from the main miktex input tree. the file in the current folder almost certainly should not be there, then miktex would show

("C:\Program Files\MiKTeX 2.9\tex\latex\beamer\base\beamer.cls"
("C:\Program Files\MiKTeX 2.9\tex\latex\beamer\base\beamerbasercs.sty")


What is supposed to happen is that beamerbasercs.sty is input which on line 13 has

\def\beamer@version{3.36}


which defines \beamer@version however you are showing this command as undefined.

• So what is supposed to do to solve the problem ????? – user96111 Jan 18 '16 at 8:50
• @user96111 as I said: first remove the local file beamer.cls in your document folder. Since that file is most likely the problem and only you have access to that file, hard to say more. – David Carlisle Jan 18 '16 at 8:54