diff --git a/ts/sql/Server.ts b/ts/sql/Server.ts
index 8ce1906274..12e6011639 100644
--- a/ts/sql/Server.ts
+++ b/ts/sql/Server.ts
@@ -2580,7 +2580,11 @@ function saveMessageAttachment({
       : null,
     backupMediaName: attachment.backupLocator?.mediaName,
     backupCdnNumber: attachment.backupLocator?.cdnNumber,
-    incrementalMac: attachment.incrementalMac,
+    incrementalMac:
+      // resilience to Uint8Array-stored incrementalMac values
+      typeof attachment.incrementalMac === 'string'
+        ? attachment.incrementalMac
+        : null,
     incrementalMacChunkSize: attachment.chunkSize,
     isReencryptableToSameDigest: convertOptionalBooleanToNullableInteger(
       attachment.isReencryptableToSameDigest
diff --git a/ts/test-electron/normalizedAttachments_test.ts b/ts/test-electron/normalizedAttachments_test.ts
index d060d8f56d..b474f009fd 100644
--- a/ts/test-electron/normalizedAttachments_test.ts
+++ b/ts/test-electron/normalizedAttachments_test.ts
@@ -605,4 +605,32 @@ describe('normalizes attachment references', () => {
     assert(messageFromDB, 'message was saved');
     assert.deepEqual(messageFromDB, message);
   });
+  it('handles bad data', async () => {
+    const attachment: AttachmentType = {
+      ...composeAttachment(),
+      uploadTimestamp: {
+        low: 6174,
+        high: 0,
+        unsigned: false,
+      } as unknown as number,
+      incrementalMac: Bytes.fromString('incrementalMac') as unknown as string,
+    };
+    const message = composeMessage(Date.now(), {
+      attachments: [attachment],
+    });
+
+    await DataWriter.saveMessage(message, {
+      forceSave: true,
+      ourAci: generateAci(),
+      postSaveUpdates: () => Promise.resolve(),
+    });
+
+    const messageFromDB = await DataReader.getMessageById(message.id);
+    assert(messageFromDB, 'message was saved');
+    assert.deepEqual(messageFromDB.attachments?.[0], {
+      ...attachment,
+      uploadTimestamp: undefined,
+      incrementalMac: undefined,
+    });
+  });
 });
diff --git a/ts/types/Message2.ts b/ts/types/Message2.ts
index c8c3b49f73..202235b864 100644
--- a/ts/types/Message2.ts
+++ b/ts/types/Message2.ts
@@ -690,6 +690,10 @@ const toVersion14 = _withSchemaVersion({
     }
   ),
 });
+const toVersion15 = _withSchemaVersion({
+  schemaVersion: 15,
+  upgrade: noopUpgrade,
+});
 
 const VERSIONS = [
   toVersion0,
@@ -707,6 +711,7 @@ const VERSIONS = [
   toVersion12,
   toVersion13,
   toVersion14,
+  toVersion15,
 ];
 
 export const CURRENT_SCHEMA_VERSION = VERSIONS.length - 1;