diff --git a/UI/window-basic-main-outputs.cpp b/UI/window-basic-main-outputs.cpp
index d6e2624cf..e569d26ed 100644
--- a/UI/window-basic-main-outputs.cpp
+++ b/UI/window-basic-main-outputs.cpp
@@ -1205,7 +1205,7 @@ bool SimpleOutput::ConfigureRecording(bool updateReplayBuffer)
 	const char *path =
 		config_get_string(main->Config(), "SimpleOutput", "FilePath");
 	const char *format =
-		config_get_string(main->Config(), "SimpleOutput", "RecFormat");
+		config_get_string(main->Config(), "SimpleOutput", "RecFormat2");
 	const char *mux = config_get_string(main->Config(), "SimpleOutput",
 					    "MuxerCustom");
 	bool noSpace = config_get_bool(main->Config(), "SimpleOutput",
@@ -1703,7 +1703,7 @@ inline void AdvancedOutput::SetupRecording()
 	int tracks;
 
 	const char *recFormat =
-		config_get_string(main->Config(), "AdvOut", "RecFormat");
+		config_get_string(main->Config(), "AdvOut", "RecFormat2");
 
 	bool is_fragmented = strcmp(recFormat, "fmp4") == 0 ||
 			     strcmp(recFormat, "fmov") == 0;
@@ -2124,7 +2124,7 @@ bool AdvancedOutput::StartRecording()
 							 : "RecFilePath");
 		recFormat = config_get_string(main->Config(), "AdvOut",
 					      ffmpegRecording ? "FFExtension"
-							      : "RecFormat");
+							      : "RecFormat2");
 		filenameFormat = config_get_string(main->Config(), "Output",
 						   "FilenameFormatting");
 		overwriteIfExists = config_get_bool(main->Config(), "Output",
@@ -2227,7 +2227,7 @@ bool AdvancedOutput::StartReplayBuffer()
 							 : "RecFilePath");
 		recFormat = config_get_string(main->Config(), "AdvOut",
 					      ffmpegRecording ? "FFExtension"
-							      : "RecFormat");
+							      : "RecFormat2");
 		filenameFormat = config_get_string(main->Config(), "Output",
 						   "FilenameFormatting");
 		overwriteIfExists = config_get_bool(main->Config(), "Output",
diff --git a/UI/window-basic-main.cpp b/UI/window-basic-main.cpp
index 4e81e78a0..7cc94006c 100644
--- a/UI/window-basic-main.cpp
+++ b/UI/window-basic-main.cpp
@@ -1378,6 +1378,13 @@ static const double scaled_vals[] = {1.0,         1.25, (1.0 / 0.75), 1.5,
 				     2.5,         2.75, 3.0,          0.0};
 
 extern void CheckExistingCookieId();
+#if OBS_RELEASE_CANDIDATE == 0 && OBS_BETA == 0
+#define DEFAULT_CONTAINER "mkv"
+#elif defined(__APPLE__)
+#define DEFAULT_CONTAINER "fmov"
+#else
+#define DEFAULT_CONTAINER "fmp4"
+#endif
 
 bool OBSBasic::InitBasicConfigDefaults()
 {
@@ -1472,6 +1479,26 @@ bool OBSBasic::InitBasicConfigDefaults()
 		}
 	}
 
+	/* ----------------------------------------------------- */
+	/* Migrate old container selection (if any) to new key.  */
+	if (!config_has_user_value(basicConfig, "SimpleOutput", "RecFormat2") &&
+	    config_has_user_value(basicConfig, "SimpleOutput", "RecFormat")) {
+		const char *old_format = config_get_string(
+			basicConfig, "SimpleOutput", "RecFormat");
+		config_set_string(basicConfig, "SimpleOutput", "RecFormat2",
+				  old_format);
+		changed = true;
+	}
+
+	if (!config_has_user_value(basicConfig, "AdvOut", "RecFormat2") &&
+	    config_has_user_value(basicConfig, "AdvOut", "RecFormat")) {
+		const char *old_format =
+			config_get_string(basicConfig, "AdvOut", "RecFormat");
+		config_set_string(basicConfig, "AdvOut", "RecFormat2",
+				  old_format);
+		changed = true;
+	}
+
 	/* ----------------------------------------------------- */
 
 	if (changed)
@@ -1486,8 +1513,8 @@ bool OBSBasic::InitBasicConfigDefaults()
 
 	config_set_default_string(basicConfig, "SimpleOutput", "FilePath",
 				  GetDefaultVideoSavePath().c_str());
-	config_set_default_string(basicConfig, "SimpleOutput", "RecFormat",
-				  "mkv");
+	config_set_default_string(basicConfig, "SimpleOutput", "RecFormat2",
+				  DEFAULT_CONTAINER);
 	config_set_default_uint(basicConfig, "SimpleOutput", "VBitrate", 2500);
 	config_set_default_uint(basicConfig, "SimpleOutput", "ABitrate", 160);
 	config_set_default_bool(basicConfig, "SimpleOutput", "UseAdvanced",
@@ -1519,7 +1546,8 @@ bool OBSBasic::InitBasicConfigDefaults()
 
 	config_set_default_string(basicConfig, "AdvOut", "RecFilePath",
 				  GetDefaultVideoSavePath().c_str());
-	config_set_default_string(basicConfig, "AdvOut", "RecFormat", "mkv");
+	config_set_default_string(basicConfig, "AdvOut", "RecFormat2",
+				  DEFAULT_CONTAINER);
 	config_set_default_bool(basicConfig, "AdvOut", "RecUseRescale", false);
 	config_set_default_uint(basicConfig, "AdvOut", "RecTracks", (1 << 0));
 	config_set_default_string(basicConfig, "AdvOut", "RecEncoder", "none");
diff --git a/UI/window-basic-settings.cpp b/UI/window-basic-settings.cpp
index 2f1ec0d6a..6114e703b 100644
--- a/UI/window-basic-settings.cpp
+++ b/UI/window-basic-settings.cpp
@@ -1909,7 +1909,7 @@ void OBSBasicSettings::LoadSimpleOutputSettings()
 	bool noSpace = config_get_bool(main->Config(), "SimpleOutput",
 				       "FileNameWithoutSpace");
 	const char *format =
-		config_get_string(main->Config(), "SimpleOutput", "RecFormat");
+		config_get_string(main->Config(), "SimpleOutput", "RecFormat2");
 	int videoBitrate =
 		config_get_uint(main->Config(), "SimpleOutput", "VBitrate");
 	const char *streamEnc = config_get_string(
@@ -2166,7 +2166,7 @@ void OBSBasicSettings::LoadAdvOutputRecordingSettings()
 	const char *type =
 		config_get_string(main->Config(), "AdvOut", "RecType");
 	const char *format =
-		config_get_string(main->Config(), "AdvOut", "RecFormat");
+		config_get_string(main->Config(), "AdvOut", "RecFormat2");
 	const char *path =
 		config_get_string(main->Config(), "AdvOut", "RecFilePath");
 	bool noSpace = config_get_bool(main->Config(), "AdvOut",
@@ -3825,7 +3825,7 @@ void OBSBasicSettings::SaveOutputSettings()
 	SaveCombo(ui->simpleOutputABitrate, "SimpleOutput", "ABitrate");
 	SaveEdit(ui->simpleOutputPath, "SimpleOutput", "FilePath");
 	SaveCheckBox(ui->simpleNoSpace, "SimpleOutput", "FileNameWithoutSpace");
-	SaveComboData(ui->simpleOutRecFormat, "SimpleOutput", "RecFormat");
+	SaveComboData(ui->simpleOutRecFormat, "SimpleOutput", "RecFormat2");
 	SaveCheckBox(ui->simpleOutAdvanced, "SimpleOutput", "UseAdvanced");
 	SaveComboData(ui->simpleOutPreset, "SimpleOutput", presetType);
 	SaveEdit(ui->simpleOutCustom, "SimpleOutput", "x264Settings");
@@ -3855,7 +3855,7 @@ void OBSBasicSettings::SaveOutputSettings()
 
 	SaveEdit(ui->advOutRecPath, "AdvOut", "RecFilePath");
 	SaveCheckBox(ui->advOutNoSpace, "AdvOut", "RecFileNameWithoutSpace");
-	SaveComboData(ui->advOutRecFormat, "AdvOut", "RecFormat");
+	SaveComboData(ui->advOutRecFormat, "AdvOut", "RecFormat2");
 	SaveComboData(ui->advOutRecEncoder, "AdvOut", "RecEncoder");
 	SaveComboData(ui->advOutRecAEncoder, "AdvOut", "RecAudioEncoder");
 	SaveCheckBox(ui->advOutRecUseRescale, "AdvOut", "RecRescale");