diff --git a/src/NetSparkle/AppCastHandlers/AppCastHelper.cs b/src/NetSparkle/AppCastHandlers/AppCastHelper.cs
index 912609c1..ef9cb5dd 100644
--- a/src/NetSparkle/AppCastHandlers/AppCastHelper.cs
+++ b/src/NetSparkle/AppCastHandlers/AppCastHelper.cs
@@ -75,7 +75,8 @@ public AppCastHelper()
         /// <param name="installedVersion">installed version of the software</param>
         /// <param name="signatureVerifier">Object to check signatures of app cast information</param>
         /// <param name="logWriter">object that you can utilize to do any necessary logging</param>
-        public virtual void SetupAppCastHelper(IAppCastDataDownloader dataDownloader, string castUrl, string? installedVersion, ISignatureVerifier? signatureVerifier, ILogger? logWriter = null)
+        public virtual void SetupAppCastHelper(IAppCastDataDownloader dataDownloader, string castUrl, 
+            string? installedVersion, ISignatureVerifier? signatureVerifier, ILogger? logWriter = null)
         {
             _dataDownloader = dataDownloader;
             _installedVersion = installedVersion;
@@ -245,7 +246,9 @@ public virtual List<AppCastItem> FilterUpdates(List<AppCastItem> items)
             }
 
             var signatureNeeded = IsSignatureNeeded();
-            _logWriter?.PrintMessage("Looking for available updates; our installed version is {0}; do we need a signature? {1}; are we filtering out smaller versions than our current version? {2}", installedVersion, signatureNeeded, shouldFilterOutSmallerVersions);
+            _logWriter?.PrintMessage("Looking for available updates; our installed version is {0}; " +
+                "do we need a signature? {1}; are we filtering out smaller versions than our " +
+                "current version? {2}", installedVersion, signatureNeeded, shouldFilterOutSmallerVersions);
             return items.Where((item) =>
             {
                 var filterResult = FilterAppCastItem(installedVersion, shouldFilterOutSmallerVersions, signatureNeeded, item);
@@ -262,7 +265,8 @@ public virtual List<AppCastItem> FilterUpdates(List<AppCastItem> items)
                         return false;
                     }
                     // accept all valid items
-                    _logWriter?.PrintMessage("Item with version {0} ({1}) is a valid update! It can be downloaded at {2}", item.Version ?? "[Unknown version]", item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
+                    _logWriter?.PrintMessage("Item with version {0} ({1}) is a valid update! It can be downloaded at {2}", 
+                        item.Version ?? "[Unknown version]", item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
                     return true;
                 }
                 return false;
@@ -337,17 +341,23 @@ protected FilterItemResult FilterAppCastItemByOS(AppCastItem item)
             // operating system
             if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && !item.IsWindowsUpdate)
             {
-                _logWriter?.PrintMessage("Rejecting update for {0} ({1}, {2}) because it isn't a Windows update and we're on Windows", item.Version ?? "[Unknown version]", item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
+                _logWriter?.PrintMessage("Rejecting update for {0} ({1}, {2}) because it isn't a Windows " +
+                    "update and we're on Windows", item.Version ?? "[Unknown version]", 
+                    item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
                 return FilterItemResult.NotThisPlatform;
             }
             else if (RuntimeInformation.IsOSPlatform(OSPlatform.OSX) && !item.IsMacOSUpdate)
             {
-                _logWriter?.PrintMessage("Rejecting update for {0} ({1}, {2}) because it isn't a macOS update and we're on macOS", item.Version ?? "[Unknown version]", item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
+                _logWriter?.PrintMessage("Rejecting update for {0} ({1}, {2}) because it isn't a macOS " +
+                    "update and we're on macOS", item.Version ?? "[Unknown version]", 
+                    item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
                 return FilterItemResult.NotThisPlatform;
             }
             else if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux) && !item.IsLinuxUpdate)
             {
-                _logWriter?.PrintMessage("Rejecting update for {0} ({1}, {2}) because it isn't a Linux update and we're on Linux", item.Version ?? "[Unknown version]", item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
+                _logWriter?.PrintMessage("Rejecting update for {0} ({1}, {2}) because it isn't a Linux " +
+                    "update and we're on Linux", item.Version ?? "[Unknown version]", 
+                    item.ShortVersion ?? "[Unknown short version]", item.DownloadLink ?? "[Unknown download link]");
                 return FilterItemResult.NotThisPlatform;
             }
 #endif
diff --git a/src/NetSparkle/Configurations/Configuration.cs b/src/NetSparkle/Configurations/Configuration.cs
index 34566dcd..63794c95 100644
--- a/src/NetSparkle/Configurations/Configuration.cs
+++ b/src/NetSparkle/Configurations/Configuration.cs
@@ -26,7 +26,7 @@ public abstract class Configuration
         /// <summary>
         /// The currently-installed version, e.g. "1.4.3"
         /// </summary>
-        public string InstalledVersion { get; protected set; }
+        public string? InstalledVersion { get; protected set; }
         /// <summary>
         /// Flag to indicate if we should check for updates
         /// </summary>
diff --git a/src/NetSparkle/Configurations/RegistryConfiguration.cs b/src/NetSparkle/Configurations/RegistryConfiguration.cs
index edd21d37..f8d97f64 100644
--- a/src/NetSparkle/Configurations/RegistryConfiguration.cs
+++ b/src/NetSparkle/Configurations/RegistryConfiguration.cs
@@ -224,7 +224,10 @@ private bool SaveValuesToPath(string regPath)
             key.SetValue("SkipThisVersion", LastVersionSkipped ?? "", RegistryValueKind.String);
             key.SetValue("DidRunOnce", DidRunOnce.ToString(), RegistryValueKind.String);
             key.SetValue("LastProfileUpdate", ConvertDateToString(LastConfigUpdate), RegistryValueKind.String);
-            key.SetValue("PreviousVersionRun", InstalledVersion, RegistryValueKind.String);
+            if (InstalledVersion != null)
+            {
+                key.SetValue("PreviousVersionRun", InstalledVersion, RegistryValueKind.String);
+            }
 
             return true;
         }
diff --git a/src/NetSparkle/SparkleUpdater.cs b/src/NetSparkle/SparkleUpdater.cs
index c5221987..40168d65 100644
--- a/src/NetSparkle/SparkleUpdater.cs
+++ b/src/NetSparkle/SparkleUpdater.cs
@@ -756,7 +756,7 @@ protected async Task<UpdateInfo> GetUpdateStatus(Configuration config, bool igno
             // check if the version will be the same then the installed version
             if (updates.Count == 0)
             {
-                LogWriter?.PrintMessage("Installed version is latest, no update needed ({0})", config.InstalledVersion);
+                LogWriter?.PrintMessage("Installed version is latest, no update needed ({0})", config.InstalledVersion ?? "[no installed version]");
                 return new UpdateInfo(UpdateStatus.UpdateNotAvailable, updates);
             }
             LogWriter?.PrintMessage("Latest version on the server is {0}", updates[0].Version ?? "[Unknown]");
@@ -1789,7 +1789,8 @@ private async Task<UpdateInfo> CheckForUpdates(bool isUserManuallyCheckingForUpd
             if (_latestDownloadedUpdateInfo.Status == UpdateStatus.UpdateAvailable)
             {
                 // there's an update available!
-                LogWriter?.PrintMessage("Update needed from version {0} to version {1}", config.InstalledVersion, updates[0].Version ?? "[unknown version]");
+                LogWriter?.PrintMessage("Update needed from version {0} to version {1}", 
+                    config.InstalledVersion ?? "[no installed version]", updates[0].Version ?? "[unknown version]");
 
                 UpdateDetectedEventArgs ev = new UpdateDetectedEventArgs(
                     NextUpdateAction.ShowStandardUserInterface,
@@ -1979,7 +1980,8 @@ private async void OnWorkerDoWork()
                             {
                                 List<AppCastItem> updates = _latestDownloadedUpdateInfo.Updates;
                                 // show the update window
-                                LogWriter?.PrintMessage("Update needed from version {0} to version {1}", config.InstalledVersion, updates[0].Version ?? "[Unknown version]");
+                                LogWriter?.PrintMessage("Update needed from version {0} to version {1}", 
+                                    config.InstalledVersion ?? "[no installed version]", updates[0].Version ?? "[Unknown version]");
 
                                 // send notification if needed
                                 UpdateDetectedEventArgs ev = new UpdateDetectedEventArgs(