diff --git a/chrome/content/zotero/preferences/preferences.js b/chrome/content/zotero/preferences/preferences.js
index ffc58eeef1..5772838325 100644
--- a/chrome/content/zotero/preferences/preferences.js
+++ b/chrome/content/zotero/preferences/preferences.js
@@ -354,7 +354,7 @@ function handleSyncReset(action) {
 			var index = pr.confirmEx(
 				// TODO: localize
 				Zotero.getString('general.warning'),
-				"All item data belonging to user '" + account + "' on the Zotero server "
+				"All data belonging to user '" + account + "' on the Zotero server "
 					+ "will be erased and replaced with data from this copy of Zotero.",
 				buttonFlags,
 				"Replace Server Data",
@@ -368,8 +368,7 @@ function handleSyncReset(action) {
 						Zotero.Sync.Server.sync(function () {
 							pr.alert(
 								"Restore Completed",
-								"Item data on the Zotero server has been "
-									+ "successfully restored."
+								"Data on the Zotero server has been successfully restored."
 							);
 						});
 					});
@@ -382,6 +381,40 @@ function handleSyncReset(action) {
 			
 			break;
 		
+		case 'full-sync':
+			var buttonFlags = (pr.BUTTON_POS_0) * (pr.BUTTON_TITLE_IS_STRING)
+							+ (pr.BUTTON_POS_1) * (pr.BUTTON_TITLE_CANCEL)
+							+ pr.BUTTON_POS_1_DEFAULT;
+			var index = pr.confirmEx(
+				// TODO: localize
+				Zotero.getString('general.warning'),
+				"The local Zotero library will be completely merged with data belonging to user '" + account + "' on the Zotero server. "
+					+ "Any unsynced changes will appear as conflicts.\n\n"
+					+ "This option should generally be used only for troubleshooting sync errors.",
+				buttonFlags,
+				"Sync",
+				null, null, null, {}
+			);
+			
+			switch (index) {
+				case 0:
+					// TODO: better error handling
+					Zotero.Sync.Server.resetClient();
+					Zotero.Sync.Server.sync(function () {
+						pr.alert(
+							"Full Sync Completed",
+							"The local Zotero library has been merged with data from the Zotero server."
+						);
+					});
+					break;
+				
+				// Cancel
+				case 1:
+					return;
+			}
+			
+			break;
+		
 		default:
 			throw ("Invalid action '" + action + "' in handleSyncReset()");
 	}
diff --git a/chrome/content/zotero/preferences/preferences.xul b/chrome/content/zotero/preferences/preferences.xul
index e8ee0ae9b3..22a5dc1ef1 100644
--- a/chrome/content/zotero/preferences/preferences.xul
+++ b/chrome/content/zotero/preferences/preferences.xul
@@ -341,10 +341,18 @@ To add a new preference:
 								</columns>
 								
 								<rows>
-									<row id="zotero-restore-from-server" selected="true">
+									<row id="zotero-full-sync">
 									<radio/>
 										<vbox onclick="this.previousSibling.click()">
-											<label value="Restore from Zotero server"/>
+											<label value="Full Sync with Zotero Server"/>
+											<description>Merge local Zotero data with data from the sync server, ignoring sync history.</description>
+										</vbox>
+									</row>
+									
+									<row id="zotero-restore-from-server" selected="true">
+										<radio/>
+										<vbox onclick="this.previousSibling.click()">
+											<label value="Restore from Zotero Server"/>
 											<description>Erase all local Zotero data and restore from the sync server.</description>
 										</vbox>
 									</row>
@@ -352,7 +360,7 @@ To add a new preference:
 									<row id="zotero-restore-to-server">
 										<radio/>
 										<vbox onclick="this.previousSibling.click()">
-											<label value="Restore to Zotero server"/>
+											<label value="Restore to Zotero Server"/>
 											<description>Erase all server data and overwrite with local Zotero data.</description>
 										</vbox>
 									</row>