diff --git a/src/main/java/org/qortal/repository/hsqldb/HSQLDBATRepository.java b/src/main/java/org/qortal/repository/hsqldb/HSQLDBATRepository.java
index d2463c80..b5779c65 100644
--- a/src/main/java/org/qortal/repository/hsqldb/HSQLDBATRepository.java
+++ b/src/main/java/org/qortal/repository/hsqldb/HSQLDBATRepository.java
@@ -415,13 +415,17 @@ public class HSQLDBATRepository implements ATRepository {
 
 	@Override
 	public void setAtTrimHeight(int trimHeight) throws DataException {
-		String updateSql = "UPDATE DatabaseInfo SET AT_trim_height = ?";
+		// trimHeightsLock is to prevent concurrent update on DatabaseInfo
+		// that could result in "transaction rollback: serialization failure"
+		synchronized (this.repository.trimHeightsLock) {
+			String updateSql = "UPDATE DatabaseInfo SET AT_trim_height = ?";
 
-		try {
-			this.repository.executeCheckedUpdate(updateSql, trimHeight);
-		} catch (SQLException e) {
-			repository.examineException(e);
-			throw new DataException("Unable to set AT state trim height in repository", e);
+			try {
+				this.repository.executeCheckedUpdate(updateSql, trimHeight);
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to set AT state trim height in repository", e);
+			}
 		}
 	}
 
diff --git a/src/main/java/org/qortal/repository/hsqldb/HSQLDBBlockRepository.java b/src/main/java/org/qortal/repository/hsqldb/HSQLDBBlockRepository.java
index 8d544e0b..de76d17b 100644
--- a/src/main/java/org/qortal/repository/hsqldb/HSQLDBBlockRepository.java
+++ b/src/main/java/org/qortal/repository/hsqldb/HSQLDBBlockRepository.java
@@ -477,13 +477,17 @@ public class HSQLDBBlockRepository implements BlockRepository {
 
 	@Override
 	public void setOnlineAccountsSignaturesTrimHeight(int trimHeight) throws DataException {
-		String updateSql = "UPDATE DatabaseInfo SET online_signatures_trim_height = ?";
+		// trimHeightsLock is to prevent concurrent update on DatabaseInfo
+		// that could result in "transaction rollback: serialization failure"
+		synchronized (this.repository.trimHeightsLock) {
+			String updateSql = "UPDATE DatabaseInfo SET online_signatures_trim_height = ?";
 
-		try {
-			this.repository.executeCheckedUpdate(updateSql, trimHeight);
-		} catch (SQLException e) {
-			repository.examineException(e);
-			throw new DataException("Unable to set online accounts signatures trim height in repository", e);
+			try {
+				this.repository.executeCheckedUpdate(updateSql, trimHeight);
+			} catch (SQLException e) {
+				repository.examineException(e);
+				throw new DataException("Unable to set online accounts signatures trim height in repository", e);
+			}
 		}
 	}
 
diff --git a/src/main/java/org/qortal/repository/hsqldb/HSQLDBRepository.java b/src/main/java/org/qortal/repository/hsqldb/HSQLDBRepository.java
index 8391d7ae..dd53e742 100644
--- a/src/main/java/org/qortal/repository/hsqldb/HSQLDBRepository.java
+++ b/src/main/java/org/qortal/repository/hsqldb/HSQLDBRepository.java
@@ -60,6 +60,7 @@ public class HSQLDBRepository implements Repository {
 	protected List<String> sqlStatements;
 	protected long sessionId;
 	protected final Map<String, PreparedStatement> preparedStatementCache = new HashMap<>();
+	protected final Object trimHeightsLock = new Object();
 
 	private final ATRepository atRepository = new HSQLDBATRepository(this);
 	private final AccountRepository accountRepository = new HSQLDBAccountRepository(this);