https://issues.dlang.org/show_bug.cgi?id=23969 --- Comment #2 from Walter Bright <bugzilla at digitalmars.com> --- What Microsoft has to say about it: https://learn.microsoft.com/en-us/cpp/parallel/thread-local-storage-tls?view=msvc-170 TL/DR: exporting TLS from DLLs causes a system crash. --