diff --git a/build/common.targets b/build/common.targets
index d526a2bb7..f26149984 100644
--- a/build/common.targets
+++ b/build/common.targets
@@ -1,7 +1,7 @@
 <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <!--set general build properties -->
-    <Version>3.12.0</Version>
+    <Version>3.12.1</Version>
     <Product>SMAPI</Product>
     <LangVersion>latest</LangVersion>
     <AssemblySearchPaths>$(AssemblySearchPaths);{GAC}</AssemblySearchPaths>
diff --git a/docs/release-notes.md b/docs/release-notes.md
index 36f071296..16744b24f 100644
--- a/docs/release-notes.md
+++ b/docs/release-notes.md
@@ -1,8 +1,19 @@
 ← [README](README.md)
 
 # Release notes
+## 3.12.1
+Released 03 August 2021 for Stardew Valley 1.5.4 or later.
+
+* For players:
+  * The software conflict message is now shown as a warning to simplify troubleshooting.
+  * Fixed error loading older Harmony mods for some Windows players using unofficial 64-bit Stardew Valley.
+  * Updated compatibility list.
+
+* For mod authors:
+  * Fixed `Constants.Save*` fields incorrect if the save's folder name and ID don't match.
+
 ## 3.12.0
-01 August 2021 for Stardew Valley 1.5.4 or later. See [release highlights](https://www.patreon.com/posts/54388616).
+Released 01 August 2021 for Stardew Valley 1.5.4 or later. See [release highlights](https://www.patreon.com/posts/54388616).
 
 * For players:
   * Added save recovery when content mods leave null objects in the save (in _Error Handler_).
diff --git a/src/SMAPI.Mods.ConsoleCommands/manifest.json b/src/SMAPI.Mods.ConsoleCommands/manifest.json
index 09684f325..7023180b9 100644
--- a/src/SMAPI.Mods.ConsoleCommands/manifest.json
+++ b/src/SMAPI.Mods.ConsoleCommands/manifest.json
@@ -1,9 +1,9 @@
 {
     "Name": "Console Commands",
     "Author": "SMAPI",
-    "Version": "3.12.0",
+    "Version": "3.12.1",
     "Description": "Adds SMAPI console commands that let you manipulate the game.",
     "UniqueID": "SMAPI.ConsoleCommands",
     "EntryDll": "ConsoleCommands.dll",
-    "MinimumApiVersion": "3.12.0"
+    "MinimumApiVersion": "3.12.1"
 }
diff --git a/src/SMAPI.Mods.ErrorHandler/manifest.json b/src/SMAPI.Mods.ErrorHandler/manifest.json
index c83ca3d08..8aa2a6a44 100644
--- a/src/SMAPI.Mods.ErrorHandler/manifest.json
+++ b/src/SMAPI.Mods.ErrorHandler/manifest.json
@@ -1,9 +1,9 @@
 {
     "Name": "Error Handler",
     "Author": "SMAPI",
-    "Version": "3.12.0",
+    "Version": "3.12.1",
     "Description": "Handles some common vanilla errors to log more useful info or avoid breaking the game.",
     "UniqueID": "SMAPI.ErrorHandler",
     "EntryDll": "ErrorHandler.dll",
-    "MinimumApiVersion": "3.12.0"
+    "MinimumApiVersion": "3.12.1"
 }
diff --git a/src/SMAPI.Mods.SaveBackup/manifest.json b/src/SMAPI.Mods.SaveBackup/manifest.json
index 42f1af594..dbd65cbec 100644
--- a/src/SMAPI.Mods.SaveBackup/manifest.json
+++ b/src/SMAPI.Mods.SaveBackup/manifest.json
@@ -1,9 +1,9 @@
 {
     "Name": "Save Backup",
     "Author": "SMAPI",
-    "Version": "3.12.0",
+    "Version": "3.12.1",
     "Description": "Automatically backs up all your saves once per day into its folder.",
     "UniqueID": "SMAPI.SaveBackup",
     "EntryDll": "SaveBackup.dll",
-    "MinimumApiVersion": "3.12.0"
+    "MinimumApiVersion": "3.12.1"
 }
diff --git a/src/SMAPI.Web/wwwroot/SMAPI.metadata.json b/src/SMAPI.Web/wwwroot/SMAPI.metadata.json
index eeda13eb9..7dff16c4f 100644
--- a/src/SMAPI.Web/wwwroot/SMAPI.metadata.json
+++ b/src/SMAPI.Web/wwwroot/SMAPI.metadata.json
@@ -167,6 +167,60 @@
             "~ | StatusReasonPhrase": "split-screen mode was added in Stardew Valley 1.5"
         },
 
+        /*********
+        ** Broke in SMAPI 3.12.0
+        *********/
+        "PlatoTK": {
+            "ID": "Platonymous.PlatoTK",
+            "~1.9.3 | Status": "AssumeBroken",
+            "~1.9.3 | StatusReasonDetails": "fails to load with 'ReflectionTypeLoadException' error"
+        },
+        "Stardew Hack": {
+            "ID": "bcmpinc.StardewHack",
+            "~5.0.0 | Status": "AssumeBroken",
+            "~5.0.0 | StatusReasonDetails": "causes Harmony patching errors for other mods"
+        },
+        "Always Scroll Map": {
+            "ID": "bcmpinc.AlwaysScrollMap",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Fix Animal Tools": {
+            "ID": "bcmpinc.FixAnimalTools",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Harvest With Scythe (bcmpinc)": {
+            "ID": "bcmpinc.HarvestWithScythe",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Grass Growth": {
+            "ID": "bcmpinc.GrassGrowth",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Tilled Soil Decay": {
+            "ID": "bcmpinc.TilledSoilDecay",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Movement Speed": {
+            "ID": "bcmpinc.MovementSpeed",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Tree Spread": {
+            "ID": "bcmpinc.TreeSpread",
+            "~4.2.0 | Status": "AssumeBroken",
+            "~4.2.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+        "Wear More Rings": {
+            "ID": "bcmpinc.WearMoreRings",
+            "~4.1.0 | Status": "AssumeBroken",
+            "~4.1.0 | StatusReasonDetails": "causes Harmony patching errors for other mods" // requested by the mod author
+        },
+
         /*********
         ** Broke in SDV 1.5 (Content Patcher packs)
         *********/
@@ -222,18 +276,6 @@
             "~1.0.8 | StatusReasonDetails": "crashes on save load"
         },
 
-        "Movement Speed": {
-            "ID": "bcmpinc.MovementSpeed",
-            "~3.0.0 | Status": "AssumeBroken",
-            "~3.0.0 | StatusReasonDetails": "broken due to transpiler errors"
-        },
-
-        "Tree Spread": {
-            "ID": "bcmpinc.TreeSpread",
-            "~3.0.0 | Status": "AssumeBroken",
-            "~3.0.0 | StatusReasonDetails": "broken due to transpiler errors"
-        },
-
         "TreeTransplant": {
             "ID": "TreeTransplant",
             "~1.0.9 | Status": "AssumeBroken",
diff --git a/src/SMAPI/Constants.cs b/src/SMAPI/Constants.cs
index 3877e17a3..058009707 100644
--- a/src/SMAPI/Constants.cs
+++ b/src/SMAPI/Constants.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using System.Reflection;
 using StardewModdingAPI.Enums;
 using StardewModdingAPI.Framework;
@@ -61,7 +60,7 @@ internal static class EarlyConstants
         internal static int? LogScreenId { get; set; }
 
         /// <summary>SMAPI's current raw semantic version.</summary>
-        internal static string RawApiVersion = "3.12.0";
+        internal static string RawApiVersion = "3.12.1";
     }
 
     /// <summary>Contains SMAPI's constants and assumptions.</summary>
@@ -165,6 +164,9 @@ public static class Constants
         /// <summary>The language code for non-translated mod assets.</summary>
         internal static LocalizedContentManager.LanguageCode DefaultLanguage { get; } = LocalizedContentManager.LanguageCode.en;
 
+        /// <summary>The name of the last save file loaded by the game.</summary>
+        internal static string LastRawSaveFileName { get; set; }
+
 
         /*********
         ** Internal methods
@@ -341,30 +343,9 @@ private static DirectoryInfo GetSaveFolder()
             if (Context.LoadStage == LoadStage.None)
                 return null;
 
-            // get basic info
-            string rawSaveName = Game1.GetSaveGameName(set_value: false);
-            ulong saveID = Context.LoadStage == LoadStage.SaveParsed
-                ? SaveGame.loaded.uniqueIDForThisGame
-                : Game1.uniqueIDForThisGame;
-
-            // get best match (accounting for rare case where folder name isn't sanitized)
-            DirectoryInfo folder = null;
-            foreach (string saveName in new[] { rawSaveName, new string(rawSaveName.Where(char.IsLetterOrDigit).ToArray()) })
-            {
-                try
-                {
-                    folder = new DirectoryInfo(Path.Combine(Constants.SavesPath, $"{saveName}_{saveID}"));
-                    if (folder.Exists)
-                        return folder;
-                }
-                catch (ArgumentException)
-                {
-                    // ignore invalid path
-                }
-            }
-
-            // if save doesn't exist yet, return the default one we expect to be created
-            return folder;
+            // get save
+            string rawSaveName = Constants.LastRawSaveFileName;
+            return new DirectoryInfo(Path.Combine(Constants.SavesPath, rawSaveName));
         }
     }
 }
diff --git a/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs b/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs
index 3606eb665..2b71038ad 100644
--- a/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs
+++ b/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs
@@ -61,6 +61,7 @@ public AssemblyLoader(Platform targetPlatform, GameFramework framework, IMonitor
             this.AssemblyDefinitionResolver = this.TrackForDisposal(new AssemblyDefinitionResolver());
             this.AssemblyDefinitionResolver.AddSearchDirectory(Constants.ExecutionPath);
             this.AssemblyDefinitionResolver.AddSearchDirectory(Constants.InternalFilesPath);
+            this.AssemblyDefinitionResolver.Add(AssemblyDefinition.ReadAssembly(typeof(SGame).Assembly.Location)); // for some reason Mono.Cecil can't resolve SMAPI in very specific cases involving unofficial 64-bit Stardew Valley when launched through Steam (for some players only)
 
             // generate type => assembly lookup for types which should be rewritten
             this.TypeAssemblies = new Dictionary<string, Assembly>();
diff --git a/src/SMAPI/Framework/SCore.cs b/src/SMAPI/Framework/SCore.cs
index a34b3eff7..3f97bd4e5 100644
--- a/src/SMAPI/Framework/SCore.cs
+++ b/src/SMAPI/Framework/SCore.cs
@@ -257,6 +257,7 @@ public void RunInteractively()
                 MiniMonoModHotfix.Apply();
                 HarmonyPatcher.Apply("SMAPI", this.Monitor,
                     new Game1Patcher(this.Reflection, this.OnLoadStageChanged),
+                    new SaveGamePatcher(this.OnSaveFileReading),
                     new TitleMenuPatcher(this.OnLoadStageChanged)
                 );
 
@@ -1101,6 +1102,13 @@ internal void OnLoadStageChanged(LoadStage newStage)
                 this.EventManager.ReturnedToTitle.RaiseEmpty();
         }
 
+        /// <summary>Raised before the game begins reading a save file.</summary>
+        /// <param name="fileName">The save folder name.</param>
+        internal void OnSaveFileReading(string fileName)
+        {
+            Constants.LastRawSaveFileName = fileName;
+        }
+
         /// <summary>Apply fixes to the save after it's loaded.</summary>
         private void ApplySaveFixes()
         {
@@ -1315,7 +1323,7 @@ private void CheckForSoftwareConflicts()
                     .ToArray();
 
                 if (installedNames.Any())
-                    this.Monitor.Log($"   Found {string.Join(" and ", installedNames)} installed, which can conflict with SMAPI. If you experience errors or crashes, try disabling that software or adding an exception for SMAPI / Stardew Valley.");
+                    this.Monitor.Log($"Found {string.Join(" and ", installedNames)} installed, which may conflict with SMAPI. If you experience errors or crashes, try disabling that software or adding an exception for SMAPI and Stardew Valley.", LogLevel.Warn);
                 else
                     this.Monitor.Log("   None found!");
             }
diff --git a/src/SMAPI/Patches/SaveGamePatcher.cs b/src/SMAPI/Patches/SaveGamePatcher.cs
new file mode 100644
index 000000000..969c514e4
--- /dev/null
+++ b/src/SMAPI/Patches/SaveGamePatcher.cs
@@ -0,0 +1,55 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using HarmonyLib;
+using StardewModdingAPI.Internal.Patching;
+using StardewValley;
+using StardewValley.Menus;
+
+namespace StardewModdingAPI.Patches
+{
+    /// <summary>Harmony patches for <see cref="SaveGame"/> which track the last loaded save ID.</summary>
+    /// <remarks>Patch methods must be static for Harmony to work correctly. See the Harmony documentation before renaming patch arguments.</remarks>
+    [SuppressMessage("ReSharper", "InconsistentNaming", Justification = "Argument names are defined by Harmony and methods are named for clarity.")]
+    [SuppressMessage("ReSharper", "IdentifierTypo", Justification = "Argument names are defined by Harmony and methods are named for clarity.")]
+    internal class SaveGamePatcher : BasePatcher
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>A callback to invoke when a save file is being loaded.</summary>
+        private static Action<string> OnSaveFileReading;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="onSaveFileReading">A callback to invoke when a save file is being loaded.</param>
+        public SaveGamePatcher(Action<string> onSaveFileReading)
+        {
+            SaveGamePatcher.OnSaveFileReading = onSaveFileReading;
+        }
+
+        /// <inheritdoc />
+        public override void Apply(Harmony harmony, IMonitor monitor)
+        {
+            harmony.Patch(
+                original: this.RequireMethod<SaveGame>(nameof(SaveGame.getLoadEnumerator)),
+                prefix: this.GetHarmonyMethod(nameof(SaveGamePatcher.Before_GetLoadEnumerator))
+            );
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>The method to call before <see cref="TitleMenu.createdNewCharacter"/>.</summary>
+        /// <returns>Returns whether to execute the original method.</returns>
+        /// <remarks>This method must be static for Harmony to work correctly. See the Harmony documentation before renaming arguments.</remarks>
+        private static bool Before_GetLoadEnumerator(string file)
+        {
+            SaveGamePatcher.OnSaveFileReading(file);
+            return true;
+        }
+    }
+}