Not him, but I can reproduce the issue when trying to add WaveShell 9.91 as a VST 2.x extension:
Unhandled exception: c0000005
Date/Time: 2017-05-10, 19:59:06
Fault address: 7FF8CDB999F8 (d:\program files (x86)\obs-studio\obs-plugins\64bit\obs-vst.dll)
libobs version: 18.0.1
Windows version: 10.0 build 14393 (revision: 1198; 64-bit)
CPU: Intel(R) Core(TM) i7-6850K CPU @ 3.60GHz
Thread 4978 (Crashed)
Stack EIP Arg0 Arg1 Arg2 Arg3 Address
0000000EDCAF9F40 00007FF8CDB999F8 000002040761C960 0000000EDCAFA030 0000000000000000 0000000EDCAFA030 obs-vst.dll!VSTPlugin::loadEffect+0x118
0000000EDCAF9F90 00007FF8CDB98E32 0000000000000000 0000020402101760 0000000000000000 00007FF8C7244030 obs-vst.dll!VSTPlugin::loadEffectFromPath+0x82
0000000EDCAFA010 00007FF8CDB977B3 00000204020C0640 0000000000000000 0000020407620F50 000000005F4FB048 obs-vst.dll!vst_update+0x93
0000000EDCAFA060 00007FF6F22C6609 000000005EFB9470 000000005EFB9470 0000000000000000 000000005EC77E5C obs64.exe!WidgetInfo::ControlChanged+0x109
0000000EDCAFA1D0 000000005EC6107D 000002040249C240 000002040000000C 0000000000000000 0000000EDCAFA300 qt5core.dll!0x5ec6107d
0000000EDCAFA2E0 000000005F0FDB56 0000000E00000020 00000204074BD7F0 0000000EDCAFA698 0000020402821270 qt5widgets.dll!0x5f0fdb56
0000000EDCAFA350 000000005F10496E 0000000000000000 000000005EAABFB5 000000005ED2DE00 0000000EDCAFA698 qt5widgets.dll!0x5f10496e
0000000EDCAFA3D0 000000005F0FDCF7 0000000E00000000 000000005EFB96F8 000000000000000D 0000020407620F50 qt5widgets.dll!0x5f0fdcf7
0000000EDCAFA460 000000005EC6107D 0000020407620F50 0000020400000007 0000000000000208 0000000EDCAFA5A0 qt5core.dll!0x5ec6107d
0000000EDCAFA570 000000005F0FF954 0000000000000000 000002040249C280 0000000EDCAFB330 000002040249C280 qt5widgets.dll!0x5f0ff954
0000000EDCAFA6E0 000000005EC4443D 000002046AB436B0 000002046AB00F50 000002040249C280 0000000EDCAFB330 qt5core.dll!0x5ec4443d
0000000EDCAFA740 000000005F007C8C 0000000000000000 0000000EDCAFA870 0000000EDCAFB330 000002046AB436B0 qt5widgets.dll!0x5f007c8c
0000000EDCAFA770 000000005F005913 00000204026E7F50 000002046AB2A180 0000000EDCAFB330 000002040249C200 qt5widgets.dll!0x5f005913
0000000EDCAFAEB0 000000005EC423C9 3FF0000000000000 0000000000000000 0000000EDCAFB350 000000005F0359C5 qt5core.dll!0x5ec423c9
0000000EDCAFAF30 000000005F008FD1 0000000EDCAFBF01 000002040249C280 0000000EDCAFBF00 0000010600000077 qt5widgets.dll!0x5f008fd1
0000000EDCAFB040 000000005F059815 0000020402302BF0 0000000EDCAFBF00 000002046AB7EB01 0000020400000000 qt5widgets.dll!0x5f059815
0000000EDCAFB3E0 000000005F057DC3 0000020402302BF0 000002046AB436B0 0000020402302BF0 0000000EDCAFBF00 qt5widgets.dll!0x5f057dc3
0000000EDCAFB450 000000005F007CA0 000002046AB436B0 0000000EDCAFB580 0000000EDCAFBF00 000002046AB436B0 qt5widgets.dll!0x5f007ca0
0000000EDCAFB480 000000005F006BFA 0000000EDCAFF970 000002046AB2A180 0000000EDCAFBF00 0000020402302B00 qt5widgets.dll!0x5f006bfa
0000000EDCAFBBC0 000000005EC423C9 0000000000000000 000002046DE88160 0000000000000000 00007FF887057E7E qt5core.dll!0x5ec423c9
0000000EDCAFBC40 00007FF887071C2C 000002046DE88160 0000000E00000000 0000000000000000 00007FF800000003 qt5gui.dll!0x7ff887071c2c
0000000EDCAFC0D0 00007FF887074140 00007FF88740B3A0 00007FF8C3C36F7F 000002046AB2A1B0 0000000000000000 qt5gui.dll!0x7ff887074140
0000000EDCAFC120 00007FF88705844C 0000000000000024 00007FF88740B3A0 0000000000000000 0000000000000000 qt5gui.dll!0x7ff88705844c
0000000EDCAFC160 000000005EC87B25 0000000080000012 00007FF8E22F3552 0000000000000000 0000000000000000 qt5core.dll!0x5ec87b25
0000000EDCAFC270 00007FF8E22E1C24 000002046B247A20 000000005EC877A0 0000000000090F90 0000000EDC930800 user32.dll!0x7ff8e22e1c24
0000000EDCAFC3D0 00007FF8E22E156C 0000000EDCAFC490 0000000006000301 0000000EDCAFC550 0000000000000000 user32.dll!0x7ff8e22e156c
0000000EDCAFC450 000000005EC87299 0000000000000000 0000020400000024 0000000000000000 0000000EDCAFF970 qt5core.dll!0x5ec87299
0000000EDCAFF7E0 00007FF8C3C36F59 000002046AB436B0 0000020400000014 0000000EDCAFF8B8 000002046AB2A180 qwindows.dll!0x7ff8c3c36f59
0000000EDCAFF810 000000005EC3EDA1 000002046AB26C90 0000020400000000 000002046AB2A180 00007FF6F231F800 qt5core.dll!0x5ec3eda1
0000000EDCAFF890 000000005EC41237 000002046AB39BE0 00007FF6F231F800 0000000EDCAFFB60 000002046AB353E0 qt5core.dll!0x5ec41237
0000000EDCAFF900 00007FF6F21EE343 0000000000000000 000002046AB361C0 0000000000000000 0000000000000000 obs64.exe!run_program+0x1a3
0000000EDCAFFA60 00007FF6F21F0374 0000000000000000 0000000000000000 0000000000000000 000002046AB361C0 obs64.exe!main+0x5a4
0000000EDCAFFC20 00007FF6F22F5925 000002046AB035D8 0000000000000000 0000000000000001 0000000000000000 obs64.exe!WinMain+0x155
0000000EDCAFFCB0 00007FF6F22F5305 0000000000000000 0000000000000000 0000000000000000 0000000000000000 obs64.exe!__tmainCRTStartup+0x149
0000000EDCAFFCF0 00007FF8E27A8364 0000000000000000 0000000000000000 0000000000000000 0000000000000000 kernel32.dll!0x7ff8e27a8364
0000000EDCAFFD20 00007FF8E44B70D1 0000000000000000 0000000000000000 0000000000000000 0000000000000000 ntdll.dll!0x7ff8e44b70d1