diff --git a/src/Paket.Core/Simplifier.fs b/src/Paket.Core/Simplifier.fs
index 42a7349fe4..a1b3ec14b9 100644
--- a/src/Paket.Core/Simplifier.fs
+++ b/src/Paket.Core/Simplifier.fs
@@ -47,6 +47,8 @@ let Simplify (dependenciesFileName,interactive) =
     if not <| File.Exists dependenciesFileName then
         failwithf "%s file not found." dependenciesFileName
     let depFile = DependenciesFile.ReadFromFile dependenciesFileName
+    if depFile.Options.Strict then
+        failwith "Strict mode detected. Will not attempt to simplify dependencies."
     let lockFilePath = depFile.FindLockfile()
     if not <| File.Exists(lockFilePath.FullName) then 
         failwith "lock file not found. Create lock file by running paket install."