diff --git a/Ghidra/Framework/DB/src/main/java/db/DBHandle.java b/Ghidra/Framework/DB/src/main/java/db/DBHandle.java
index b75a2a545a..be6eaddc38 100644
--- a/Ghidra/Framework/DB/src/main/java/db/DBHandle.java
+++ b/Ghidra/Framework/DB/src/main/java/db/DBHandle.java
@@ -519,6 +519,7 @@ public class DBHandle {
 				if (commit) {
 					masterTable.flush();
 					if (bufferMgr.checkpoint()) {
+						cachedChangedState = isChanged();
 						++checkpointNum;
 						return true;
 					}
@@ -532,15 +533,13 @@ public class DBHandle {
 			}
 		}
 		finally {
-			if (commit) {
-				cachedChangedState = isChanged();
-			}
 			txStarted = false;
 		}
 		return false;
 	}
 
 	private void cacheChangedState() {
+		// Must be invoked from within a synchronized block when no transaction is active
 		cachedChangedState = bufferMgr != null && bufferMgr.isChanged();
 	}
 
@@ -550,7 +549,10 @@ public class DBHandle {
 	 * 
 	 * @return current modification count
 	 */
-	public long getModCount() {
+	public synchronized long getModCount() {
+		if (bufferMgr == null) {
+			return txStartingModCount; // ballpark value (database has been closed)
+		}
 		return bufferMgr.getModCount();
 	}
 
@@ -715,26 +717,6 @@ public class DBHandle {
 		return tables.size();
 	}
 
-	/**
-	 * Revert the current database version to an older version.
-	 * @param oldVersion
-	 * @param monitor
-	 * @return boolean
-	 * @throws IllegalStateException if the database has modified prior to
-	 * invoking this method.
-	 * @throws IllegalArgumentException if this method is invoked more than
-	 * once or the version file(s) are corrupt.
-	 */
-//	boolean revert(int oldVersion, TaskMonitor monitor) throws IOException {
-//		for (int v = (version-1); v >= oldVersion; --v) {
-//			monitor.setMessage("Processing Version " + v);
-//			bufferMgr.applyVersionFile(db.getVersionFile(v), monitor);
-//			if (monitor.isCancelled())
-//				return false;
-//		}
-//		return true;
-//	}
-
 	/**
 	 * Close the database and dispose of the underlying buffer manager.
 	 * Any existing recovery data will be discarded.
@@ -773,8 +755,8 @@ public class DBHandle {
 	 * 
 	 * @return true if unsaved changes have been made.
 	 */
-	public boolean isChanged() {
-		if (txStarted) {
+	public synchronized boolean isChanged() {
+		if (bufferMgr != null && txStarted) {
 			return cachedChangedState || txStartingModCount != getModCount();
 		}
 		return cachedChangedState;