diff --git a/chrome/content/zotero/xpcom/storage/webdav.js b/chrome/content/zotero/xpcom/storage/webdav.js
index 70264119b1..0f8c03aa6a 100644
--- a/chrome/content/zotero/xpcom/storage/webdav.js
+++ b/chrome/content/zotero/xpcom/storage/webdav.js
@@ -446,7 +446,10 @@ Zotero.Sync.Storage.Mode.WebDAV.prototype = {
 						yield item.saveTx({ skipAll: true });
 						// skipAll doesn't mark as unsynced, so do that separately
 						yield item.updateSynced(false);
-						return new Zotero.Sync.Storage.Result;
+						return new Zotero.Sync.Storage.Result({
+							localChanges: true,
+							syncRequired: true
+						});
 					}
 				}
 				
@@ -463,9 +466,20 @@ Zotero.Sync.Storage.Mode.WebDAV.prototype = {
 				if (smtime != mtime) {
 					let shash = item.attachmentSyncedHash;
 					if (shash && metadata.md5 && shash == metadata.md5) {
-						Zotero.debug("Last synced mod time for item " + item.libraryKey
-							+ " doesn't match time on storage server but hash does -- ignoring");
-						return new Zotero.Sync.Storage.Result;
+						Zotero.debug(`Last synced mod time for item ${item.libraryKey} doesn't `
+							+ "match time on storage server but hash does -- using local file mtime");
+						
+						yield this._setStorageFileMetadata(item);
+						item.attachmentSyncedModificationTime = fmtime;
+						item.attachmentSyncState = "in_sync";
+						yield item.saveTx({ skipAll: true });
+						// skipAll doesn't mark as unsynced, so do that separately
+						yield item.updateSynced(false);
+						
+						return new Zotero.Sync.Storage.Result({
+							localChanges: true,
+							syncRequired: true
+						});
 					}
 					
 					Zotero.logError("Conflict -- last synced file mod time for item "
diff --git a/test/tests/webdavTest.js b/test/tests/webdavTest.js
index ddc3c4eb6f..0cf25d466d 100644
--- a/test/tests/webdavTest.js
+++ b/test/tests/webdavTest.js
@@ -517,11 +517,6 @@ describe("Zotero.Sync.Storage.Mode.WebDAV", function () {
 			yield item.saveTx();
 			var mtime = yield item.attachmentModificationTime;
 			var hash = yield item.attachmentHash;
-			var path = item.getFilePath();
-			var filename = 'test.png';
-			var size = (yield OS.File.stat(path)).size;
-			var contentType = 'image/png';
-			var fileContents = yield Zotero.File.getContentsAsync(path);
 			
 			setResponse({
 				method: "GET",
@@ -537,15 +532,61 @@ describe("Zotero.Sync.Storage.Mode.WebDAV", function () {
 			
 			assertRequestCount(1);
 			
-			assert.isFalse(result.localChanges);
+			assert.isTrue(result.localChanges);
 			assert.isFalse(result.remoteChanges);
-			assert.isFalse(result.syncRequired);
+			assert.isTrue(result.syncRequired);
 			
 			// Check local object
 			assert.equal(item.attachmentSyncedModificationTime, mtime);
 			assert.equal(item.attachmentSyncedHash, hash);
 			assert.isFalse(item.synced);
-		})
+		});
+		
+		it("should skip upload and update mtimes if synced mtime doesn't match WebDAV mtime but file hash does", async function () {
+			var engine = await setup();
+			
+			var file = OS.Path.join(getTestDataDirectory().path, 'test.png');
+			var item = await Zotero.Attachments.importFromFile({ file });
+			await item.saveTx();
+			var fmtime = await item.attachmentModificationTime;
+			var hash = await item.attachmentHash;
+			
+			var mtime = 123456789000;
+			var mtime2 = 123456799000;
+			item.attachmentSyncedModificationTime = mtime;
+			item.attachmentSyncedHash = hash;
+			item.attachmentSyncState = 'to_upload';
+			item.synced = true;
+			await item.saveTx();
+			
+			setResponse({
+				method: "GET",
+				url: `zotero/${item.key}.prop`,
+				status: 200,
+				text: '<properties version="1">'
+					+ `<mtime>${mtime2}</mtime>`
+					+ `<hash>${hash}</hash>`
+					+ '</properties>'
+			});
+			setResponse({
+				method: "PUT",
+				url: `zotero/${item.key}.prop`,
+				status: 204
+			});
+			
+			var result = await engine.start();
+			
+			assertRequestCount(2);
+			
+			assert.isTrue(result.localChanges);
+			assert.isFalse(result.remoteChanges);
+			assert.isTrue(result.syncRequired);
+			
+			// Check local object
+			assert.equal(item.attachmentSyncedModificationTime, fmtime);
+			assert.equal(item.attachmentSyncedHash, hash);
+			assert.isFalse(item.synced);
+		});
 		
 		
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