diff --git a/Ghidra/Framework/Project/src/main/java/ghidra/framework/data/DomainObjectAdapterDB.java b/Ghidra/Framework/Project/src/main/java/ghidra/framework/data/DomainObjectAdapterDB.java
index 9e89620737..43d9617d05 100644
--- a/Ghidra/Framework/Project/src/main/java/ghidra/framework/data/DomainObjectAdapterDB.java
+++ b/Ghidra/Framework/Project/src/main/java/ghidra/framework/data/DomainObjectAdapterDB.java
@@ -583,12 +583,16 @@ public abstract class DomainObjectAdapterDB extends DomainObjectAdapter implemen
 		}
 
 		DomainObjectAdapterDB userData = getUserData();
-		if (userData != null && userData.isChanged() && (getDomainFile() instanceof GhidraFile)) {
+		if (canSave() && userData != null && userData.isChanged() &&
+			(getDomainFile() instanceof GhidraFile)) {
+			// Only save user data if this domain object was open for update and the
+			// user data was modified.
 			try {
 				userData.prepareToSave();
 				userData.save(null, TaskMonitor.DUMMY);
 			}
 			catch (CancelledException e) {
+				// ignore
 			}
 			catch (IOException e) {
 				Msg.warn(this, "Failed to save user data for: " + getDomainFile().getName());
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramContentHandler.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramContentHandler.java
index d5ee0f23e4..ca4ebe3731 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramContentHandler.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramContentHandler.java
@@ -28,6 +28,7 @@ import ghidra.framework.model.ChangeSet;
 import ghidra.framework.model.DomainObject;
 import ghidra.framework.store.*;
 import ghidra.framework.store.local.LocalDatabaseItem;
+import ghidra.program.model.lang.LanguageNotFoundException;
 import ghidra.util.InvalidNameException;
 import ghidra.util.Msg;
 import ghidra.util.exception.CancelledException;
@@ -232,9 +233,25 @@ public class ProgramContentHandler extends DBWithUserDataContentHandler<ProgramD
 		DBHandle userDbh =
 			openAssociatedUserFile(programItem.getFileID(), PROGRAM_CONTENT_TYPE, userfs, monitor);
 		if (userDbh != null) {
-			return new ProgramUserDataDB(userDbh, program, monitor);
+			boolean success = false;
+			try {
+				ProgramUserDataDB data = new ProgramUserDataDB(userDbh, program, monitor);
+				success = true;
+				return data;
+			}
+			catch (LanguageNotFoundException | IllegalStateException e) {
+				// Ignore - delete to make way for new one
+			}
+			finally {
+				if (!success) {
+					userDbh.close();
+					Msg.debug(this, "Removing incompatible program user data file for " +
+						programItem.getPathName());
+					removeUserDataFile(programItem, userfs);
+				}
+			}
 		}
-		return new ProgramUserDataDB(program);
+		return null; // will be created by ProgramDB when modified
 	}
 
 	private void recoverChangeSet(ProgramDB program, DBHandle dbh) throws IOException {
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramDB.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramDB.java
index bcf87805aa..8e54841181 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramDB.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramDB.java
@@ -1910,8 +1910,12 @@ public class ProgramDB extends DomainObjectAdapterDB implements Program, ChangeM
 	}
 
 	@Override
-	protected void setChanged(boolean b) {
-		super.setChanged(b);
+	protected void setChanged(boolean state) {
+		super.setChanged(state);
+		if (!state && !dbh.isChanged()) {
+			// language upgrade has already been completed
+			languageUpgradeTranslator = null;
+		}
 	}
 
 	void setChangeSet(ProgramDBChangeSet changeSet) {
@@ -2369,6 +2373,12 @@ public class ProgramDB extends DomainObjectAdapterDB implements Program, ChangeM
 
 	@Override
 	protected void close() {
+		if (changed && languageUpgradeTranslator != null) {
+			// Prevent user data from being saved if program and user data 
+			// have gone through a major language upgrade and the program
+			// was not saved.
+			programUserData.setChanged(false);
+		}
 		super.close();
 		intRangePropertyMap.clear();
 		addrSetPropertyMap.clear();
diff --git a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramUserDataDB.java b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramUserDataDB.java
index f115f0fcc0..a9703dafb0 100644
--- a/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramUserDataDB.java
+++ b/Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/ProgramUserDataDB.java
@@ -119,6 +119,11 @@ class ProgramUserDataDB extends DomainObjectAdapterDB implements ProgramUserData
 		return program.getName() + "_UserData";
 	}
 
+	/**
+	 * Create a new program user data store.
+	 * @param program related program
+	 * @throws IOException if an IO error occurs
+	 */
 	public ProgramUserDataDB(ProgramDB program) throws IOException {
 		super(new DBHandle(), getName(program), 500, program);
 		this.program = program;
@@ -157,8 +162,22 @@ class ProgramUserDataDB extends DomainObjectAdapterDB implements ProgramUserData
 		}
 	}
 
+	/**
+	 * Open existing program user data store.
+	 * If a major language change is detected the instance will automatically attempt to upgrade
+	 * its internal address map.
+	 * @param dbh user data storage DB handle
+	 * @param program related program
+	 * @param monitor task monitor
+	 * @throws IOException if an IO error occurs
+	 * @throws VersionException if a DB version error occurs
+	 * @throws LanguageNotFoundException if language was not found
+	 * @throws CancelledException if instantiation was cancelled
+	 * @throws IllegalStateException if data store is bad or incmopatible with program
+	 */
 	public ProgramUserDataDB(DBHandle dbh, ProgramDB program, TaskMonitor monitor)
-			throws IOException, VersionException, LanguageNotFoundException, CancelledException {
+			throws IOException, VersionException, LanguageNotFoundException, CancelledException,
+			IllegalStateException {
 
 		super(dbh, getName(program), 500, program);
 		this.program = program;
@@ -200,6 +219,9 @@ class ProgramUserDataDB extends DomainObjectAdapterDB implements ProgramUserData
 			upgradeDatabase();
 
 			if (languageVersionExc != null) {
+				if (languageUpgradeTranslator == null) {
+					throw new LanguageNotFoundException(languageID + ":" + languageVersion);
+				}
 				try {
 					setLanguage(languageUpgradeTranslator, monitor);
 					addressMap.memoryMapChanged(program.getMemory());
@@ -212,6 +234,16 @@ class ProgramUserDataDB extends DomainObjectAdapterDB implements ProgramUserData
 				}
 			}
 
+			if (!program.getLanguageID().equals(languageID)) {
+				throw new IllegalStateException(
+					"User data and program have inconsistent language ID");
+			}
+
+			if (program.getLanguage().getVersion() != languageVersion) {
+				throw new IllegalStateException(
+					"User data language version does not match program's");
+			}
+
 			endTransaction(id, true);
 			changed = false;
 			clearUndo(false);
@@ -431,6 +463,10 @@ class ProgramUserDataDB extends DomainObjectAdapterDB implements ProgramUserData
 			record.setString(VALUE_COL, languageID.getIdAsString());
 			table.putRecord(record);
 
+			record = SCHEMA.createRecord(new StringField(LANGUAGE_VERSION));
+			record.setString(VALUE_COL, Integer.toString(languageVersion));
+			table.putRecord(record);
+
 			setChanged(true);
 			clearCache(true);
 
@@ -451,6 +487,11 @@ class ProgramUserDataDB extends DomainObjectAdapterDB implements ProgramUserData
 		return dbh.canUpdate();
 	}
 
+	@Override
+	protected void setChanged(boolean b) {
+		super.setChanged(b);
+	}
+	
 	private PropertyMap<?> getPropertyMap(String owner, String propertyName, int propertyType,
 			Class<?> saveableClass, boolean create) throws PropertyTypeMismatchException {