diff --git a/ArchiSteamFarm/Compatibility/SupportedOSPlatformAttribute.cs b/ArchiSteamFarm/Compatibility/SupportedOSPlatformAttribute.cs
new file mode 100644
index 000000000..dad4d260b
--- /dev/null
+++ b/ArchiSteamFarm/Compatibility/SupportedOSPlatformAttribute.cs
@@ -0,0 +1,35 @@
+//     _                _      _  ____   _                           _____
+//    / \    _ __  ___ | |__  (_)/ ___| | |_  ___   __ _  _ __ ___  |  ___|__ _  _ __  _ __ ___
+//   / _ \  | '__|/ __|| '_ \ | |\___ \ | __|/ _ \ / _` || '_ ` _ \ | |_  / _` || '__|| '_ ` _ \
+//  / ___ \ | |  | (__ | | | || | ___) || |_|  __/| (_| || | | | | ||  _|| (_| || |   | | | | | |
+// /_/   \_\|_|   \___||_| |_||_||____/  \__|\___| \__,_||_| |_| |_||_|   \__,_||_|   |_| |_| |_|
+// |
+// Copyright 2015-2021 Łukasz "JustArchi" Domeradzki
+// Contact: JustArchi@JustArchi.net
+// |
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// |
+// http://www.apache.org/licenses/LICENSE-2.0
+// |
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#if NETFRAMEWORK
+using System;
+using JetBrains.Annotations;
+
+namespace ArchiSteamFarm.Compatibility {
+	[AttributeUsage(AttributeTargets.Assembly | AttributeTargets.Class | AttributeTargets.Constructor | AttributeTargets.Enum | AttributeTargets.Event | AttributeTargets.Field | AttributeTargets.Method | AttributeTargets.Module | AttributeTargets.Property | AttributeTargets.Struct, AllowMultiple = true, Inherited = false)]
+	[PublicAPI]
+	public sealed class SupportedOSPlatformAttribute : Attribute {
+		public string PlatformName { get; }
+
+		public SupportedOSPlatformAttribute(string platformName) => PlatformName = platformName;
+	}
+}
+#endif
diff --git a/ArchiSteamFarm/Core/OS.cs b/ArchiSteamFarm/Core/OS.cs
index 099bdb5f6..c15d3b559 100644
--- a/ArchiSteamFarm/Core/OS.cs
+++ b/ArchiSteamFarm/Core/OS.cs
@@ -178,11 +178,9 @@ namespace ArchiSteamFarm.Core {
 			return true;
 		}
 
-#if !NETFRAMEWORK
 		[SupportedOSPlatform("FreeBSD")]
 		[SupportedOSPlatform("Linux")]
 		[SupportedOSPlatform("OSX")]
-#endif
 		internal static void UnixSetFileAccess(string path, EUnixPermission permission) {
 			if (string.IsNullOrEmpty(path)) {
 				throw new ArgumentNullException(nameof(path));
@@ -250,9 +248,7 @@ namespace ArchiSteamFarm.Core {
 #endif
 		}
 
-#if !NETFRAMEWORK
 		[SupportedOSPlatform("Windows")]
-#endif
 		private static void WindowsDisableQuickEditMode() {
 #if NETFRAMEWORK
 			if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) {
@@ -277,9 +273,7 @@ namespace ArchiSteamFarm.Core {
 			}
 		}
 
-#if !NETFRAMEWORK
 		[SupportedOSPlatform("Windows")]
-#endif
 		private static void WindowsKeepSystemActive() {
 #if NETFRAMEWORK
 			if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows)) {
@@ -301,11 +295,9 @@ namespace ArchiSteamFarm.Core {
 		}
 
 		[Flags]
-#if !NETFRAMEWORK
 		[SupportedOSPlatform("FreeBSD")]
 		[SupportedOSPlatform("Linux")]
 		[SupportedOSPlatform("OSX")]
-#endif
 		internal enum EUnixPermission : ushort {
 			OtherExecute = 0x1,
 			OtherWrite = 0x2,
@@ -321,64 +313,46 @@ namespace ArchiSteamFarm.Core {
 		}
 
 		private static class NativeMethods {
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal const EExecutionState AwakeExecutionState = EExecutionState.SystemRequired | EExecutionState.AwayModeRequired | EExecutionState.Continuous;
 
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal const uint EnableQuickEditMode = 0x0040;
 
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal const sbyte StandardInputHandle = -10;
 
 #pragma warning disable CA2101 // False positive, we can't use unicode charset on Unix, and it uses UTF-8 by default anyway
 			[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
 			[DllImport("libc", EntryPoint = "chmod", SetLastError = true)]
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("FreeBSD")]
 			[SupportedOSPlatform("Linux")]
 			[SupportedOSPlatform("OSX")]
-#endif
 			internal static extern int Chmod(string path, int mode);
 #pragma warning restore CA2101 // False positive, we can't use unicode charset on Unix, and it uses UTF-8 by default anyway
 
 			[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
 			[DllImport("kernel32.dll")]
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal static extern bool GetConsoleMode(IntPtr hConsoleHandle, out uint lpMode);
 
 			[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
 			[DllImport("kernel32.dll")]
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal static extern IntPtr GetStdHandle(int nStdHandle);
 
 			[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
 			[DllImport("kernel32.dll")]
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal static extern bool SetConsoleMode(IntPtr hConsoleHandle, uint dwMode);
 
 			[DefaultDllImportSearchPaths(DllImportSearchPath.System32)]
 			[DllImport("kernel32.dll")]
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal static extern EExecutionState SetThreadExecutionState(EExecutionState executionState);
 
 			[Flags]
-#if !NETFRAMEWORK
 			[SupportedOSPlatform("Windows")]
-#endif
 			internal enum EExecutionState : uint {
 				None = 0,
 				SystemRequired = 0x00000001,