diff --git a/src/app/FakeLib/FSIHelper.fs b/src/app/FakeLib/FSIHelper.fs
index 034bd6daa71..82ba680ad6d 100644
--- a/src/app/FakeLib/FSIHelper.fs
+++ b/src/app/FakeLib/FSIHelper.fs
@@ -257,12 +257,17 @@ let internal runFAKEScriptWithFsiArgsAndRedirectMessages printDetails (FsiArgs(f
             let assemVersionValidCount =
                 cacheConfig.Value.Assemblies
                 |> Seq.map(fun assemInfo ->
-                    let assem = 
-                        if assemInfo.Location <> "" then
-                            Reflection.Assembly.LoadFrom(assemInfo.Location)
-                        else
-                            Reflection.Assembly.Load(assemInfo.FullName)
-                    assem.GetName().Version.ToString() = assemInfo.Version)
+                    try
+                        let assem = 
+                            if assemInfo.Location <> "" then
+                                Reflection.Assembly.LoadFrom(assemInfo.Location)
+                            else
+                                Reflection.Assembly.Load(assemInfo.FullName)
+                        assem.GetName().Version.ToString() = assemInfo.Version
+                    with 
+                    | ex -> 
+                        if printDetails then tracef "Unable to find assembly %A" assemInfo
+                        false)
                 |> Seq.filter(fun x -> x = true)
                 |> Seq.length
 
@@ -337,14 +342,21 @@ let internal runFAKEScriptWithFsiArgsAndRedirectMessages printDetails (FsiArgs(f
                         if File.Exists("FSI-ASSEMBLY.pdb") then
                             File.Delete("FSI-ASSEMBLY.pdb")
 
-                        let refedAssemblies = 
-                            System.AppDomain.CurrentDomain.GetAssemblies()
-                            |> Seq.filter(fun assem -> not assem.IsDynamic)                            
+                        let dynamicAssemblies = 
+                            System.AppDomain.CurrentDomain.GetAssemblies() 
+                            |> Seq.filter(fun assem -> assem.IsDynamic)
+                            |> Seq.filter(fun assem -> assem.GetName().Name <> "FSI-ASSEMBLY")
+                        if dynamicAssemblies |> Seq.length > 0 then
+                            if printDetails then 
+                                trace "Dynamic assemblies were generated during evaluation of script.\nCan not save cache." 
+                        else
+                            let assemblies = 
+                                System.AppDomain.CurrentDomain.GetAssemblies()
+                                |> Seq.filter(fun assem -> not assem.IsDynamic)
                         
-                        let cacheConfig : XDocument = Cache.create refedAssemblies
-                        cacheConfig.Save(cacheConfigPath.Value) 
-
-                        if printDetails then trace (System.Environment.NewLine + "Saved cache")
+                            let cacheConfig : XDocument = Cache.create assemblies
+                            cacheConfig.Save(cacheConfigPath.Value) 
+                            if printDetails then trace (System.Environment.NewLine + "Saved cache")
                 with 
                 | ex ->
                     handleException ex