diff -r c4d84af6b609 -r c9e370c3c26c .appveyor.yml
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -6,6 +6,17 @@
   - x86
   - x64
 
+install:
+  - cinst --allow-empty-checksums smlnj
+  - ps: '"[hostfingerprints]" | Out-File -Encoding "ASCII" -Append $env:USERPROFILE\mercurial.ini'
+  - ps: '"code.soundsoftware.ac.uk = 66:ef:e2:0e:e3:55:93:9a:33:aa:2a:e9:fe:be:21:c2:a2:8d:4f:f1" | Out-File -Encoding "ASCII" -Append $env:USERPROFILE\mercurial.ini'
+  - ps: '"[hostsecurity]" | Out-File -Encoding "ASCII" -Append $env:USERPROFILE\mercurial.ini'
+  - ps: '"code.soundsoftware.ac.uk = code.soundsoftware.ac.uk:fingerprints=sha256:64:75:f6:47:15:de:b4:51:ea:96:e2:f4:8a:f5:53:a5:11:c8:dd:82:73:5d:bd:54:18:cb:c8:9d:10:37:28:85" | Out-File -Encoding "ASCII" -Append $env:USERPROFILE\mercurial.ini'
+
+before_build:
+  - set PATH=%PATH%;C:\Program Files (x86)\SMLNJ\bin
+  - vext install
+
 build:
   project: build\vamp-plugin-tester.sln