Hi One of our Ubuntu 16.04 systems has started failing a compilation today. This compilation has succeeded previously. The failure is: $ g++ -c -std=c++14 -Wall -pedantic -m64 -march=native -I../Kernel -I/net/simdata/Hudson_OpenSourceLibs/Boost/ -fpic -O3 ../StarLibs/StdStars/ArithmeticCoding.cpp -o _gnuRelease/ArithmeticCoding.o cc1plus: fatal error: /net/simdata/Hudson_OpenSourceLibs/Boost/stdc-predef.h: Input/output error compilation terminated. If I exclude the -I/net/simdata ... (which is a mounted drive) the compilation succeeds without failure. For the failure case, the search order is: ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/5" ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu" ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/5/../../../../x86_64-linux-gnu/include" #include "..." search starts here: #include <...> search starts here: ../Kernel /net/simdata/Hudson_OpenSourceLibs/Boost/ /usr/include/c++/5 /usr/include/x86_64-linux-gnu/c++/5 /usr/include/c++/5/backward /usr/lib/gcc/x86_64-linux-gnu/5/include /usr/local/include /usr/lib/gcc/x86_64-linux-gnu/5/include-fixed /usr/include/x86_64-linux-gnu /usr/include End of search list. And the file in question is indeed found at: $ ls /usr/include/stdc-predef.h /usr/include/stdc-predef.h The mount seems to be working ok: $ ls /net/simdata/Hudson_OpenSourceLibs/Boost/rel-1.69.0/boost/ accumulators dll.hpp make_unique.hpp random.hpp align dynamic_bitset math range etc. I don't understand why gcc is complaining that stdc-predef.h is not found on the mounted drive and is failing to find it in /usr/include. Can you help please? Best regards David