diff --git a/chrome/content/zotero/xpcom/storage/storageLocal.js b/chrome/content/zotero/xpcom/storage/storageLocal.js
index 2b8e9f7748..149d5c9a05 100644
--- a/chrome/content/zotero/xpcom/storage/storageLocal.js
+++ b/chrome/content/zotero/xpcom/storage/storageLocal.js
@@ -622,11 +622,11 @@ Zotero.Sync.Storage.Local = {
 		}
 		
 		if (!path) {
-			// This can happen if an HTML snapshot filename was changed and synced
-			// elsewhere but the renamed file wasn't synced, so the ZIP doesn't
-			// contain a file with the known name
-			Components.utils.reportError("File '" + item.attachmentFilename
-				+ "' not found after processing download " + item.libraryKey);
+			// This generally shouldn't happen, since if the ZIP doesn't contain the primary file,
+			// and there's only one HTML file within it, we rename it to the current filename, but
+			// it could occur if there are multiple HTML files or there's an error renaming the file.
+			Zotero.logError("File '" + item.attachmentFilename + "' not found after processing "
+				+ "download " + item.libraryKey);
 			return new Zotero.Sync.Storage.Result({
 				localChanges: false
 			});
@@ -795,6 +795,7 @@ Zotero.Sync.Storage.Local = {
 		
 		var itemFileName = item.attachmentFilename;
 		
+		var createdFiles = new Set();
 		var entries = zipReader.findEntries(null);
 		while (entries.hasMore()) {
 			var entryName = entries.getNext();
@@ -835,7 +836,7 @@ Zotero.Sync.Storage.Local = {
 				filtered = true;
 			}
 			
-			var destPath = OS.Path.join(parentDir, ...filePath.split('/'));
+			let destPath = OS.Path.join(parentDir, ...filePath.split('/'));
 			
 			// If only one file in zip and it doesn't match the known filename,
 			// take our chances and use that name
@@ -910,6 +911,7 @@ Zotero.Sync.Storage.Local = {
 			
 			try {
 				zipReader.extract(entryName, Zotero.File.pathToFile(destPath));
+				createdFiles.add(PathUtils.filename(destPath));
 			}
 			catch (e) {
 				try {
@@ -968,6 +970,23 @@ Zotero.Sync.Storage.Local = {
 			zipFile.remove(false);
 		}
 		
+		// If multiple files and none match known filename, but there's only one HTML file, rename it
+		if (!createdFiles.has(itemFileName)) {
+			Zotero.debug(`${itemFileName} not found among extracted files`);
+			let htmlFiles = [...createdFiles].filter(x => /\.html?$/.test(x));
+			if (htmlFiles.length == 1) {
+				let destPath = PathUtils.join(parentDir, itemFileName);
+				try {
+					Zotero.debug(`Renaming ${htmlFiles[0]} to ${itemFileName}`);
+					await IOUtils.move(PathUtils.join(parentDir, htmlFiles[0]), destPath);
+					returnFile = destPath;
+				}
+				catch (e) {
+					Zotero.logError(e);
+				}
+			}
+		}
+		
 		return returnFile;
 	},
 	
diff --git a/test/tests/storageLocalTest.js b/test/tests/storageLocalTest.js
index e60ad5bf4b..f825bdd856 100644
--- a/test/tests/storageLocalTest.js
+++ b/test/tests/storageLocalTest.js
@@ -549,6 +549,71 @@ describe("Zotero.Sync.Storage.Local", function () {
 				);
 				assert.equal(await item.attachmentModificationTime, mtime);
 			});
+			
+			
+			it("should rename a single HTML file in an old multi-file ZIP to match the current primary filename", async function () {
+				var libraryID = Zotero.Libraries.userLibraryID;
+				var parentItem = await createDataObject('item');
+				var key = Zotero.DataObjectUtilities.generateKey();
+				
+				var oldFilename = "a.html";
+				var auxFilename = "a.gif";
+				var newFilename = "b.html";
+				var fileContents = Zotero.Utilities.randomString();
+				var tmpDir = Zotero.getTempDirectory().path;
+				var zipFile = OS.Path.join(tmpDir, key + '.tmp');
+				
+				// Create ZIP file
+				var tmpDir = Zotero.getTempDirectory().path;
+				var zipDir = await getTempDirectory();
+				await Zotero.File.putContentsAsync(PathUtils.join(zipDir, oldFilename), fileContents);
+				await Zotero.File.putContentsAsync(PathUtils.join(zipDir, auxFilename), '');
+				await Zotero.File.zipDirectory(zipDir, zipFile);
+				await removeDir(zipDir);
+				
+				var md5 = Zotero.Utilities.Internal.md5(Zotero.File.pathToFile(zipFile));
+				var mtime = 1445667239000;
+				
+				var json = {
+					key,
+					version: 10,
+					itemType: 'attachment',
+					linkMode: 'imported_url',
+					url: 'https://example.com/foo.html',
+					filename: 'b.html',
+					contentType: 'text/plain',
+					charset: 'utf-8',
+					md5,
+					mtime
+				};
+				await Zotero.Sync.Data.Local.processObjectsFromJSON('item', libraryID, [json]);
+				
+				var item = await Zotero.Items.getByLibraryAndKeyAsync(libraryID, key);
+				
+				await Zotero.Sync.Storage.Local.processDownload({
+					item,
+					md5,
+					mtime,
+					compressed: true
+				});
+				await OS.File.remove(zipFile);
+				
+				var storageDir = Zotero.Attachments.getStorageDirectory(item).path;
+				
+				// Make sure path is set correctly
+				assert.equal(item.getFilePath(), PathUtils.join(storageDir, newFilename));
+				// Make sure previous file doesn't exist
+				assert.isFalse(await IOUtils.exists(PathUtils.join(storageDir, oldFilename)));
+				// And new ones do
+				assert.isTrue(await IOUtils.exists(PathUtils.join(storageDir, newFilename)));
+				assert.isTrue(await IOUtils.exists(PathUtils.join(storageDir, auxFilename)));
+				
+				// Make sure main file matches attachment hash and mtime
+				assert.equal(
+					await item.attachmentHash, Zotero.Utilities.Internal.md5(fileContents)
+				);
+				assert.equal(await item.attachmentModificationTime, mtime);
+			});
 		});
 	})