This is pdfTeX, Version 3.141592653-2.6-1.40.25 (TeX Live 2023/Arch Linux) (preloaded format=pdflatex 2024.2.22) 24 MAR 2024 11:03 entering extended mode \write18 enabled. %&-line parsing enabled. **custom_header.tex presentatie.tex (./custom_header.tex LaTeX2e <2022-11-01> patch level 1 L3 programming layer <2023-02-22> ! Undefined control sequence. l.2 \setbeamertemplate {headline} ? x Here is how much of TeX's memory you used: 16 strings out of 477385 418 string characters out of 5824045 1849388 words of memory out of 5000000 20354 multiletter control sequences out of 15000+600000 512287 words of font info for 32 fonts, out of 8000000 for 9000 350 hyphenation exceptions out of 8191 13i,0n,12p,66b,10s stack positions out of 10000i,1000n,20000p,200000b,200000s No pages of output. PDF statistics: 0 PDF objects out of 1000 (max. 8388607) 0 named destinations out of 1000 (max. 500000) 1 words of extra memory for PDF output out of 10000 (max. 10000000)