diff --git a/chrome/content/zotero/xpcom/schema.js b/chrome/content/zotero/xpcom/schema.js
index 9c99daa036..93d7e75e63 100644
--- a/chrome/content/zotero/xpcom/schema.js
+++ b/chrome/content/zotero/xpcom/schema.js
@@ -671,7 +671,7 @@ Zotero.Schema = new function () {
 	 * This needs the data object architecture to be initialized, so it's called from zotero.js
 	 * rather than in _updateGlobalSchema().
 	 */
-	this.migrateExtraFields = async function () {
+	this.migrateExtraFields = async function ({ onProgress }) {
 		// Check for a flag set by _updateGlobalSchema()
 		var needsUpdate = await Zotero.DB.valueQueryAsync(
 			"SELECT COUNT(*) FROM settings WHERE setting='globalSchema' AND key='migrateExtra'"
@@ -680,11 +680,14 @@ Zotero.Schema = new function () {
 			return;
 		}
 		
+		Zotero.debug("Migrating fields from Extra");
+		
 		var fieldID = Zotero.ItemFields.getID('extra');
 		var sql = "SELECT itemID, value FROM itemData "
 			+ "JOIN itemDataValues USING (valueID) "
 			+ "WHERE fieldID=?";
 		var rows = await Zotero.DB.queryAsync(sql, fieldID);
+		
 		var itemIDs = [];
 		for (let row of rows) {
 			let { itemType, fields, creators } = Zotero.Utilities.Internal.extractExtraFields(
@@ -696,14 +699,35 @@ Zotero.Schema = new function () {
 		}
 		
 		var items = await Zotero.Items.getAsync(itemIDs);
-		await Zotero.Items.loadDataTypes(items);
-		for (let item of items) {
-			let changed = item.migrateExtraFields();
-			if (!changed) continue;
-			await item.saveTx({
-				skipDateModifiedUpdate: true,
-				skipSelect: true
-			});
+		
+		Zotero.debug(`${items.length} items to migrate`);
+		
+		if (items.length) {
+			await Zotero.Items.loadDataTypes(items);
+			
+			let progress = 0;
+			let progressMax = items.length;
+			if (onProgress) {
+				onProgress({ progress, progressMax });
+			}
+			
+			let notifierQueue = new Zotero.Notifier.Queue;
+			try {
+				for (let item of items) {
+					let changed = item.migrateExtraFields();
+					if (changed) {
+						await item.saveTx({
+							skipDateModifiedUpdate: true,
+							skipSelect: true,
+							notifierQueue
+						});
+					}
+					onProgress({ progress: ++progress, progressMax });
+				}
+			}
+			finally {
+				await Zotero.Notifier.commit(notifierQueue);
+			}
 		}
 		
 		await Zotero.DB.queryAsync(
diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index dc0039528e..4687b3a2fb 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -745,9 +745,6 @@ const { CommandLineOptions } = ChromeUtils.importESModule("chrome://zotero/conte
 				}
 			});
 			
-			// Migrate fields from Extra that can be moved to item fields after a schema update
-			await Zotero.Schema.migrateExtraFields();
-			
 			Zotero.Items.startEmptyTrashTimer();
 			
 			Zotero.QuickCopy.init();
@@ -758,6 +755,49 @@ const { CommandLineOptions } = ChromeUtils.importESModule("chrome://zotero/conte
 			
 			Zotero.Schema.schemaUpdatePromise.then(Zotero.purgeDataObjects.bind(Zotero));
 			
+			// Migrate fields from Extra that can be moved to item fields after a schema update
+			//
+			// To test migration after the server has been updated, disable auto-sync and uncomment
+			// this line instead of the following one
+			//Zotero.Schema.schemaUpdatePromise.then(async () => {
+			Zotero.startupSyncPromise.then(async () => {
+				let progressWin;
+				let itemProgress;
+				// Feed updates (e.g., deleting old items) can interfere with this, so pause them
+				// until we're done
+				let feedPauser = await Zotero.Feeds.pause();
+				try {
+					await Zotero.Schema.migrateExtraFields({
+						onProgress: ({ progress, progressMax }) => {
+							if (!progressWin) {
+								progressWin = new Zotero.ProgressWindow({
+									closeOnClick: false
+								});
+								let title = Zotero.getString('upgrade.status');
+								progressWin.changeHeadline(title);
+								itemProgress = new progressWin.ItemProgress(
+									'journalArticle',
+									Zotero.getString('migrate-extra-fields-progress-message')
+								);
+								progressWin.show();
+							}
+							
+							itemProgress.setProgress(progress / progressMax * 100);
+						}
+					});
+				}
+				catch (e) {
+					Zotero.logError(e);
+					itemProgress.setError();
+				}
+				finally {
+					feedPauser.resume();
+				}
+				if (progressWin) {
+					progressWin.startCloseTimer(3000);
+				}
+			});
+			
 			return true;
 		}
 		catch (e) {
diff --git a/chrome/locale/en-US/zotero/zotero.ftl b/chrome/locale/en-US/zotero/zotero.ftl
index 082c3e94a1..083edfa2e2 100644
--- a/chrome/locale/en-US/zotero/zotero.ftl
+++ b/chrome/locale/en-US/zotero/zotero.ftl
@@ -841,6 +841,8 @@ connector-version-warning = The { -app-name } Connector must be updated to work
 
 userjs-pref-warning = Some { -app-name } settings have been overridden using an unsupported method. { -app-name } will revert them and restart.
 
+migrate-extra-fields-progress-message = Migrating new fields from Extra field
+
 long-tag-fixer-window-title =
     .title = Split Tags
 long-tag-fixer-button-dont-split =