diff --git a/chrome/content/zotero/xpcom/schema.js b/chrome/content/zotero/xpcom/schema.js
index baeab1a0b9..9c3af687cf 100644
--- a/chrome/content/zotero/xpcom/schema.js
+++ b/chrome/content/zotero/xpcom/schema.js
@@ -1515,15 +1515,37 @@ Zotero.Schema = new function(){
 			}
 			
 			// TEMP: DB diagnostics
+			let badDB = false;
 			let exists = yield Zotero.DB.tableExists('transactionSets');
 			url += "&ts=" + (exists ? "1" : "0");
 			if (exists) {
 				Zotero.logError("DB table 'transactionSets' still exists");
+				badDB = true;
 			}
 			exists = yield Zotero.DB.tableExists('dbDebug1');
 			url += "&db1=" + (exists ? "1" : "0");
 			if (!exists) {
 				Zotero.logError("DB table 'dbDebug1' does not exist");
+				badDB = true;
+			}
+			if (badDB) {
+				let cloudDir = Zotero.File.isCloudStorageFolder(Zotero.DataDirectory.dir);
+				url += "&cd=" + (cloudDir ? "1" : "0");
+				
+				if (!this._debugDBIntegrityChecked) {
+					try {
+						let dbPath = Zotero.DataDirectory.getDatabase();
+						let dbInfo = yield OS.File.stat(dbPath);
+						if (dbInfo.size < 500000000) {
+							let ok = yield Zotero.DB.quickCheck();
+							url += "&qc=" + (ok ? "1" : "0");
+							this._debugDBIntegrityChecked = true;
+						}
+					}
+					catch (e) {
+						Zotero.logError(e);
+					}
+				}
 			}
 			
 			// Send list of installed styles