diff --git a/Logic/Osm/OsmPreferences.ts b/Logic/Osm/OsmPreferences.ts
index 489b27cb8a..dc9b5c50e1 100644
--- a/Logic/Osm/OsmPreferences.ts
+++ b/Logic/Osm/OsmPreferences.ts
@@ -76,9 +76,9 @@ export class OsmPreferences {
 
 
         function updateData(l: number) {
-            if (l === undefined) {
-                source.setData(undefined);
-                return;
+            if(Object.keys(self.preferences.data).length === 0){
+                // The preferences are still empty - they are not yet updated, so we delay updating for now 
+                return
             }
             const prefsCount = Number(l);
             if (prefsCount > 100) {
@@ -86,7 +86,11 @@ export class OsmPreferences {
             }
             let str = "";
             for (let i = 0; i < prefsCount; i++) {
-                str += self.GetPreference(allStartWith + "-" + i, "").data;
+                const key = allStartWith + "-" + i
+                if(self.preferences.data[key] === undefined){
+                    console.warn("Detected a broken combined preference:", key, "is undefined", self.preferences)
+                }
+                str += self.preferences.data[key] ?? "";
             }
 
             source.setData(str);
@@ -95,7 +99,9 @@ export class OsmPreferences {
         length.addCallback(l => {
             updateData(Number(l));
         });
-        updateData(Number(length.data));
+        this.preferences.addCallbackAndRun(_ => {
+            updateData(Number(length.data));
+        })
 
         return source;
     }
@@ -127,7 +133,8 @@ export class OsmPreferences {
     public ClearPreferences() {
         let isRunning = false;
         const self = this;
-        this.preferences.addCallbackAndRun(prefs => {
+        this.preferences.addCallback(prefs => {
+            console.log("Cleaning preferences...")
             if (Object.keys(prefs).length == 0) {
                 return;
             }
@@ -135,19 +142,17 @@ export class OsmPreferences {
                 return
             }
             isRunning = true
-            const prefixes = ["mapcomplete-installed-theme", "mapcomplete-installed-themes-", "mapcomplete-current-open-changeset", "mapcomplete-personal-theme-layer"]
+            const prefixes = ["mapcomplete-"]
             for (const key in prefs) {
-                for (const prefix of prefixes) {
-                    if (key.startsWith(prefix)) {
-                        console.log("Clearing ", key)
-                        self.GetPreference(key, "").setData("")
+                const matches = prefixes.some(prefix => key.startsWith(prefix))
+                if (matches) {
+                    console.log("Clearing ", key)
+                    self.GetPreference(key, "").setData("")
 
-                    }
                 }
             }
             isRunning = false;
-            return true;
-
+            return;
         })
     }