Tikz compilation weird error

When compiling my thesis, messed up error appears.
```
Package tikz Error: Sorry, the system call 'pdflatex -shell-escape -halt-on-e
rror -interaction=batchmode -jobname "full-figure0" "\def\tikzexternalrealjob{f
ull}\input{full}"' did NOT result in a usable output file 'full-figure0' (expec
ted one of .pdf:.jpg:.jpeg:.png:).
```
The solution is to compile the whole document *without* the cover page first, then uncomment the line and compile again.