Compiler gives hundreds of "invalid character" suddenly

Question

I am writing my latex document in TexMaker and suddenly in one of the thousands of compilations I make there is a error and I cant get rid of it. The error is:

! Text line contains an invalid character.

The "funny" thing is that the error is in line 2, where I haven't changed anything for weeks and it turn out that there are 100 errors like this in the compilation, each of them with 1 more invalid character. Starts with one and then every error gives +1 character more to the string. Weird.

Has anyone had this error before? It is clear that the error is not because of the invalid character, it doesn't exist! Any ideas?

Answer 1

The following comes from the .log file you reported:

("C:\Documents and Settings\ander.biguri\Escritorio\Memoria\LaTeX\Memoria.aux"
! Text line contains an invalid character.
l.2 ! Text line contains an invalid character.

This means that the invalid character is found in the .aux file. Remove the file and retry.

Errors during a compilation may, sometimes, cause a corruption of the .aux file that is rewritten each time. The removal is a safe operation, which has the only consequence that some more LaTeX runs are needed for synchronizing cross references.

Answer 2

The following line of the error message (which you haven't shown) should show the character for example

! Text line contains an invalid character.
l.7 \begin{document}^^?

In fact I think in the default setup that is the only invalid character (delete, U+007F). So You need to delete the delete character.

Possibly your file has been saved in an incorrect encoding?

Answer 3

I encountered the same problem, a simple way to avoid these error is changing the build system to xelatex

for example, if you are using sublime text, then add the following line to the head of your .tex file:

%!TEX program = xelatex

Some people might not want to change the build system. Now let me introduce another solution. This problem is caused by the wrong file encode format. Thus you should change the file encoding format to UTF-8 (Notepad++ can help you do it).

For example, windows users might got error like zhwindowsfonts.tex:1: Text line contains an invalid character. [^^@]

xxx\texlive\texmf-dist\tex\generic\ctex\zhwindowsfonts.tex:1: Text line contains an invalid character. [^^@]
xxx\texlive\texmf-dist\tex\generic\ctex\zhwindowsfonts.tex:1: Text line contains an invalid character. [^^@^^@]

In that case, you should change the file format of zhwindowsfonts.tex. You might got error like

xxx\texlive\texmf-dist\tex\context\base\mkii\supp-pdf.mkii: Text line 

In that case, you should change the file format of supp-pdf.mkii.

The errors will be fixed after correcting the encoding format.