diff --git a/modules/juce_audio_processors/format/juce_AudioPluginFormat.h b/modules/juce_audio_processors/format/juce_AudioPluginFormat.h
index 88f263b512..c7753e0b44 100644
--- a/modules/juce_audio_processors/format/juce_AudioPluginFormat.h
+++ b/modules/juce_audio_processors/format/juce_AudioPluginFormat.h
@@ -110,6 +110,12 @@ public:
     /** Returns true if this format needs to run a scan to find its list of plugins. */
     virtual bool canScanForPlugins() const = 0;
 
+    /** Should return true if this format is both safe and quick to scan - i.e. if a file
+        can be scanned within a few milliseconds on a background thread, without actually
+        needing to load an executable.
+    */
+    virtual bool isTrivialToScan() const = 0;
+
     /** Searches a suggested set of directories for any plugins in this format.
         The path might be ignored, e.g. by AUs, which are found by the OS rather
         than manually.
@@ -144,7 +150,8 @@ protected:
     virtual void createPluginInstance (const PluginDescription&, double initialSampleRate,
                                        int initialBufferSize, PluginCreationCallback) = 0;
 
-    virtual bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept = 0;
+    /** Returns true if instantiation of this plugin type must be done from a non-message thread. */
+    virtual bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const = 0;
 
 private:
     struct AsyncCreateMessage;
diff --git a/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.h b/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.h
index 2afb4fe870..34ff650e57 100644
--- a/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.h
+++ b/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.h
@@ -43,7 +43,10 @@ public:
     ~AudioUnitPluginFormat() override;
 
     //==============================================================================
-    String getName() const override                { return "AudioUnit"; }
+    String getName() const override                 { return "AudioUnit"; }
+    bool canScanForPlugins() const override         { return true; }
+    bool isTrivialToScan() const override           { return false; }
+
     void findAllTypesForFile (OwnedArray<PluginDescription>&, const String& fileOrIdentifier) override;
     bool fileMightContainThisPluginType (const String& fileOrIdentifier) override;
     String getNameOfPluginFromIdentifier (const String& fileOrIdentifier) override;
@@ -51,17 +54,13 @@ public:
     StringArray searchPathsForPlugins (const FileSearchPath&, bool recursive, bool) override;
     bool doesPluginStillExist (const PluginDescription&) override;
     FileSearchPath getDefaultLocationsToSearch() override;
-    bool canScanForPlugins() const override        { return true; }
 
 private:
     //==============================================================================
-    void createPluginInstance (const PluginDescription&,
-                               double initialSampleRate, int initialBufferSize,
-                               PluginCreationCallback) override;
+    void createPluginInstance (const PluginDescription&, double initialSampleRate,
+                               int initialBufferSize, PluginCreationCallback) override;
+    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const override;
 
-    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept override;
-
-    //==============================================================================
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (AudioUnitPluginFormat)
 };
 
diff --git a/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm b/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm
index b8e70062e2..af6e491b87 100644
--- a/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm
+++ b/modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm
@@ -2754,7 +2754,7 @@ void AudioUnitPluginFormat::createPluginInstance (const PluginDescription& desc,
     }
 }
 
-bool AudioUnitPluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription& desc) const noexcept
+bool AudioUnitPluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription& desc) const
 {
    #if JUCE_SUPPORTS_AUv3
     String pluginName, version, manufacturer;
diff --git a/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp b/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp
index 1a8deebfdf..960b3db8b7 100644
--- a/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp
+++ b/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.cpp
@@ -653,7 +653,7 @@ void LADSPAPluginFormat::createPluginInstance (const PluginDescription& desc,
     callback (std::move (result), errorMsg);
 }
 
-bool LADSPAPluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept
+bool LADSPAPluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const
 {
     return false;
 }
diff --git a/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.h b/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.h
index 960c1fa2f3..c1f8741ddb 100644
--- a/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.h
+++ b/modules/juce_audio_processors/format_types/juce_LADSPAPluginFormat.h
@@ -42,7 +42,10 @@ public:
     ~LADSPAPluginFormat() override;
 
     //==============================================================================
-    String getName() const override                { return "LADSPA"; }
+    String getName() const override                 { return "LADSPA"; }
+    bool canScanForPlugins() const override         { return true; }
+    bool isTrivialToScan() const override           { return false; }
+
     void findAllTypesForFile (OwnedArray<PluginDescription>&, const String& fileOrIdentifier) override;
     bool fileMightContainThisPluginType (const String& fileOrIdentifier) override;
     String getNameOfPluginFromIdentifier (const String& fileOrIdentifier) override;
@@ -50,16 +53,12 @@ public:
     StringArray searchPathsForPlugins (const FileSearchPath&, bool recursive, bool) override;
     bool doesPluginStillExist (const PluginDescription&) override;
     FileSearchPath getDefaultLocationsToSearch() override;
-    bool canScanForPlugins() const override        { return true; }
 
 private:
     //==============================================================================
     void createPluginInstance (const PluginDescription&, double initialSampleRate,
                                int initialBufferSize, PluginCreationCallback) override;
-
-    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept override;
-
-private:
+    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const override;
     void recursiveFileSearch (StringArray&, const File&, bool recursive);
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (LADSPAPluginFormat)
diff --git a/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp b/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp
index 4dc3ed1670..e8290fcd30 100644
--- a/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp
+++ b/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp
@@ -3114,7 +3114,7 @@ void VST3PluginFormat::createPluginInstance (const PluginDescription& descriptio
     callback (std::move (result), errorMsg);
 }
 
-bool VST3PluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept
+bool VST3PluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const
 {
     return false;
 }
diff --git a/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.h b/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.h
index f38bdc33d3..ebb78f1724 100644
--- a/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.h
+++ b/modules/juce_audio_processors/format_types/juce_VST3PluginFormat.h
@@ -51,7 +51,10 @@ public:
     static bool setStateFromVSTPresetFile (AudioPluginInstance*, const MemoryBlock&);
 
     //==============================================================================
-    String getName() const override             { return "VST3"; }
+    String getName() const override                 { return "VST3"; }
+    bool canScanForPlugins() const override         { return true; }
+    bool isTrivialToScan() const override           { return false; }
+
     void findAllTypesForFile (OwnedArray<PluginDescription>&, const String& fileOrIdentifier) override;
     bool fileMightContainThisPluginType (const String& fileOrIdentifier) override;
     String getNameOfPluginFromIdentifier (const String& fileOrIdentifier) override;
@@ -59,16 +62,12 @@ public:
     StringArray searchPathsForPlugins (const FileSearchPath&, bool recursive, bool) override;
     bool doesPluginStillExist (const PluginDescription&) override;
     FileSearchPath getDefaultLocationsToSearch() override;
-    bool canScanForPlugins() const override     { return true; }
-
-private:
-    void createPluginInstance (const PluginDescription&, double initialSampleRate,
-                               int initialBufferSize, PluginCreationCallback) override;
-
-    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept override;
 
 private:
     //==============================================================================
+    void createPluginInstance (const PluginDescription&, double initialSampleRate,
+                               int initialBufferSize, PluginCreationCallback) override;
+    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const override;
     void recursiveFileSearch (StringArray&, const File&, bool recursive);
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (VST3PluginFormat)
diff --git a/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp b/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp
index 3b77c92fd7..35293b8b1c 100644
--- a/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp
+++ b/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.cpp
@@ -3611,7 +3611,7 @@ void VSTPluginFormat::createPluginInstance (const PluginDescription& desc,
     callback (std::move (result), errorMsg);
 }
 
-bool VSTPluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept
+bool VSTPluginFormat::requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const
 {
     return false;
 }
diff --git a/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.h b/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.h
index d66dcf581a..39519399de 100644
--- a/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.h
+++ b/modules/juce_audio_processors/format_types/juce_VSTPluginFormat.h
@@ -98,7 +98,10 @@ public:
     static AudioPluginInstance* getPluginInstanceFromVstEffectInterface (void* aEffect);
 
     //==============================================================================
-    String getName() const override                { return "VST"; }
+    String getName() const override                 { return "VST"; }
+    bool canScanForPlugins() const override         { return true; }
+    bool isTrivialToScan() const override           { return false; }
+
     void findAllTypesForFile (OwnedArray<PluginDescription>&, const String& fileOrIdentifier) override;
     bool fileMightContainThisPluginType (const String& fileOrIdentifier) override;
     String getNameOfPluginFromIdentifier (const String& fileOrIdentifier) override;
@@ -106,7 +109,6 @@ public:
     StringArray searchPathsForPlugins (const FileSearchPath&, bool recursive, bool) override;
     bool doesPluginStillExist (const PluginDescription&) override;
     FileSearchPath getDefaultLocationsToSearch() override;
-    bool canScanForPlugins() const override        { return true; }
 
     /** Can be overridden to receive a callback when each member of a shell plugin is about to be
         tested during a call to findAllTypesForFile().
@@ -119,10 +121,7 @@ private:
     //==============================================================================
     void createPluginInstance (const PluginDescription&, double initialSampleRate,
                                int initialBufferSize, PluginCreationCallback) override;
-
-    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const noexcept override;
-
-private:
+    bool requiresUnblockedMessageThreadDuringCreation (const PluginDescription&) const override;
     void recursiveFileSearch (StringArray&, const File&, bool recursive);
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (VSTPluginFormat)