diff --git a/OpenRA.Game/Game.cs b/OpenRA.Game/Game.cs
index aa961f6df2..74f476254e 100644
--- a/OpenRA.Game/Game.cs
+++ b/OpenRA.Game/Game.cs
@@ -14,6 +14,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Drawing;
 using System.Drawing.Imaging;
+using System.Globalization;
 using System.IO;
 using System.Linq;
 using System.Net;
@@ -71,9 +72,8 @@ namespace OpenRA
 
 		static string TimestampedFilename(bool includemilliseconds = false)
 		{
-			return includemilliseconds
-			? DateTime.UtcNow.ToString("OpenRA-yyyy-MM-ddTHHmmssfffZ")
-			: DateTime.UtcNow.ToString("OpenRA-yyyy-MM-ddTHHmmssZ");
+			var format = includemilliseconds ? "yyyy-MM-ddTHHmmssfffZ" : "yyyy-MM-ddTHHmmssZ";
+			return "OpenRA-" + DateTime.UtcNow.ToString(format, CultureInfo.InvariantCulture);
 		}
 
 		static void JoinInner(OrderManager om)
diff --git a/OpenRA.Game/Network/SyncReport.cs b/OpenRA.Game/Network/SyncReport.cs
index 62068d83ae..6959d05ced 100644
--- a/OpenRA.Game/Network/SyncReport.cs
+++ b/OpenRA.Game/Network/SyncReport.cs
@@ -18,6 +18,7 @@ using OpenRA.Primitives;
 
 namespace OpenRA.Network
 {
+	using System.Globalization;
 	using NamesValuesPair = Pair<string[], object[]>;
 
 	class SyncReport
@@ -92,7 +93,7 @@ namespace OpenRA.Network
 
 		internal void DumpSyncReport(int frame, IEnumerable<FrameData.ClientOrder> orders)
 		{
-			var reportName = "syncreport-" + DateTime.UtcNow.ToString("yyyy-MM-ddTHHmmssZ") + ".log";
+			var reportName = "syncreport-" + DateTime.UtcNow.ToString("yyyy-MM-ddTHHmmssZ", CultureInfo.InvariantCulture) + ".log";
 			Log.AddChannel("sync", reportName);
 
 			foreach (var r in syncReports)
diff --git a/OpenRA.Game/Support/Program.cs b/OpenRA.Game/Support/Program.cs
index ab422122b8..60e374f81b 100644
--- a/OpenRA.Game/Support/Program.cs
+++ b/OpenRA.Game/Support/Program.cs
@@ -11,6 +11,7 @@
 
 using System;
 using System.Diagnostics;
+using System.Globalization;
 using System.Linq;
 using System.Reflection;
 using System.Text;
@@ -48,7 +49,7 @@ namespace OpenRA
 
 		static void FatalError(Exception ex)
 		{
-			var exceptionName = "exception-" + DateTime.UtcNow.ToString("yyyy-MM-ddTHHmmssZ") + ".log";
+			var exceptionName = "exception-" + DateTime.UtcNow.ToString("yyyy-MM-ddTHHmmssZ", CultureInfo.InvariantCulture) + ".log";
 			Log.AddChannel("exception", exceptionName);
 
 			if (Game.ModData != null)