diff --git a/chrome/content/zotero/overlay.js b/chrome/content/zotero/overlay.js
index a344531fad..aba4a48fb4 100644
--- a/chrome/content/zotero/overlay.js
+++ b/chrome/content/zotero/overlay.js
@@ -338,6 +338,11 @@ var ZoteroPane = new function()
 			// Focus the quicksearch on pane open
 			setTimeout("document.getElementById('zotero-tb-search').inputField.select();", 1);
 			
+			var d = new Date();
+			Zotero.purgeDataObjects(true);
+			var d2 = new Date();
+			Zotero.debug("Purged data tables in " + (d2 - d) + "ms");
+			
 			if (Zotero.Prefs.get('sync.autoSync') && Zotero.Sync.Server.enabled) {
 				setTimeout(function () {
 					Zotero.Sync.Runner.sync();
diff --git a/chrome/content/zotero/xpcom/data/creator.js b/chrome/content/zotero/xpcom/data/creator.js
index a7db6eeb86..d61a65566b 100644
--- a/chrome/content/zotero/xpcom/data/creator.js
+++ b/chrome/content/zotero/xpcom/data/creator.js
@@ -409,6 +409,8 @@ Zotero.Creator.prototype.erase = function () {
 	}
 	
 	Zotero.DB.commitTransaction();
+	
+	Zotero.Prefs.set('purge.creators', true);
 }
 
 
diff --git a/chrome/content/zotero/xpcom/data/creators.js b/chrome/content/zotero/xpcom/data/creators.js
index 0ac0f24f0d..79c5989566 100644
--- a/chrome/content/zotero/xpcom/data/creators.js
+++ b/chrome/content/zotero/xpcom/data/creators.js
@@ -197,6 +197,10 @@ Zotero.Creators = new function() {
 	 * and clear internal array entries
 	 */
 	function purge() {
+		if (!Zotero.Prefs.get('purge.creators')) {
+			return;
+		}
+		
 		Zotero.debug("Purging creator tables");
 		
 		// Purge unused creators
@@ -230,6 +234,8 @@ Zotero.Creators = new function() {
 				+ "(SELECT creatorDataID FROM creators)";
 			Zotero.DB.query(sql);
 		}
+		
+		Zotero.Prefs.set('purge.creators', false);
 	}
 	
 	
diff --git a/chrome/content/zotero/xpcom/data/item.js b/chrome/content/zotero/xpcom/data/item.js
index de023edec2..723de4bbf5 100644
--- a/chrome/content/zotero/xpcom/data/item.js
+++ b/chrome/content/zotero/xpcom/data/item.js
@@ -3358,7 +3358,12 @@ Zotero.Item.prototype.erase = function(deleteChildren) {
 	Zotero.DB.query('DELETE FROM annotations WHERE itemID=?', this.id);
 	Zotero.DB.query('DELETE FROM highlights WHERE itemID=?', this.id);
 	Zotero.DB.query('DELETE FROM deletedItems WHERE itemID=?', this.id);
-	Zotero.DB.query('DELETE FROM itemCreators WHERE itemID=?', this.id);
+	var hasCreators = Zotero.DB.valueQuery(
+		"SELECT rowid FROM itemCreators WHERE itemID=? LIMIT 1", this.id
+	);
+	if (hasCreators) {
+		Zotero.DB.query('DELETE FROM itemCreators WHERE itemID=?', this.id);
+	}
 	Zotero.DB.query('DELETE FROM itemNotes WHERE itemID=?', this.id);
 	Zotero.DB.query('DELETE FROM itemAttachments WHERE itemID=?', this.id);
 	Zotero.DB.query('DELETE FROM itemSeeAlso WHERE itemID=?', this.id);
@@ -3392,6 +3397,11 @@ Zotero.Item.prototype.erase = function(deleteChildren) {
 	}
 	
 	Zotero.Notifier.trigger('delete', 'item', this.id, deletedItemNotifierData);
+	
+	Zotero.Prefs.set('purge.items', true);
+	if (hasCreators) {
+		Zotero.Prefs.set('purge.creators', true);
+	}
 }
 
 
diff --git a/chrome/content/zotero/xpcom/data/items.js b/chrome/content/zotero/xpcom/data/items.js
index 0c86af0226..03469db1d5 100644
--- a/chrome/content/zotero/xpcom/data/items.js
+++ b/chrome/content/zotero/xpcom/data/items.js
@@ -35,7 +35,6 @@ Zotero.Items = new function() {
 	this.add = add;
 	this.cacheFields = cacheFields;
 	this.erase = erase;
-	this.purge = purge;
 	this.getFirstCreatorSQL = getFirstCreatorSQL;
 	this.getSortTitle = getSortTitle;
 	
@@ -386,7 +385,7 @@ Zotero.Items = new function() {
 	function erase(ids, eraseChildren) {
 		ids = Zotero.flattenArguments(ids);
 		
-		Zotero.UnresponsiveScriptIndicator.disable();
+		var usiDisabled = Zotero.UnresponsiveScriptIndicator.disable();
 		try {
 			Zotero.DB.beginTransaction();
 			for each(var id in ids) {
@@ -399,7 +398,6 @@ Zotero.Items = new function() {
 				item.erase(eraseChildren); // calls unload()
 				item = undefined;
 			}
-			this.purge();
 			Zotero.DB.commitTransaction();
 		}
 		catch (e) {
@@ -407,31 +405,26 @@ Zotero.Items = new function() {
 			throw (e);
 		}
 		finally {
-			Zotero.UnresponsiveScriptIndicator.enable();
+			if (usiDisabled) {
+				Zotero.UnresponsiveScriptIndicator.enable();
+			}
 		}
 	}
 	
 	
-	/*
-	 * Clear entries from various tables that no longer exist
-	 *
-	 * This is called automatically by Items.erase() but must be called
-	 * manually after Item.erase()
+	/**
+	 * Purge unused data values
 	 */
-	function purge() {
-		Zotero.Creators.purge();
-		Zotero.Tags.purge();
-		Zotero.Fulltext.purgeUnusedWords();
+	this.purge = function () {
+		if (!Zotero.Prefs.get('purge.items')) {
+			return;
+		}
 		
-		// Purge unused values
 		var sql = "DELETE FROM itemDataValues WHERE valueID NOT IN "
-			+ "(SELECT valueID FROM itemData)";
+					+ "(SELECT valueID FROM itemData)";
 		Zotero.DB.query(sql);
 		
-		var ZU = new Zotero.Utilities;
-		if (Zotero.Sync.Storage.active && ZU.probability(10)) {
-			Zotero.Sync.Storage.purgeDeletedStorageFiles();
-		}
+		Zotero.Prefs.set('purge.items', false)
 	}
 	
 	
diff --git a/chrome/content/zotero/xpcom/data/tag.js b/chrome/content/zotero/xpcom/data/tag.js
index fc63d0e1c3..ba415d1e17 100644
--- a/chrome/content/zotero/xpcom/data/tag.js
+++ b/chrome/content/zotero/xpcom/data/tag.js
@@ -531,6 +531,8 @@ Zotero.Tag.prototype.erase = function () {
 	Zotero.Notifier.trigger('delete', 'tag', this.id, deletedTagNotifierData);
 	
 	Zotero.DB.commitTransaction();
+	
+	Zotero.Prefs.set('purge.tags', true);
 	return;
 }
 
diff --git a/chrome/content/zotero/xpcom/data/tags.js b/chrome/content/zotero/xpcom/data/tags.js
index 3a3476ff68..04d25ec75a 100644
--- a/chrome/content/zotero/xpcom/data/tags.js
+++ b/chrome/content/zotero/xpcom/data/tags.js
@@ -342,13 +342,17 @@ Zotero.Tags = new function() {
 	 * Returns removed tagIDs on success
 	 */
 	function purge() {
+		if (!Zotero.Prefs.get('purge.tags')) {
+			return;
+		}
+		
 		Zotero.UnresponsiveScriptIndicator.disable();
 		try {
 			Zotero.DB.beginTransaction();
 			
 			var sql = "CREATE TEMPORARY TABLE tagDelete AS "
 				+ "SELECT tagID FROM tags WHERE tagID "
-				+ "NOT IN (SELECT tagID FROM itemTags);";
+				+ "NOT IN (SELECT tagID FROM itemTags)";
 			Zotero.DB.query(sql);
 			
 			sql = "CREATE INDEX tagDelete_tagID ON tagDelete(tagID)";
@@ -361,6 +365,7 @@ Zotero.Tags = new function() {
 				sql = "DROP TABLE tagDelete";
 				Zotero.DB.query(sql);
 				Zotero.DB.commitTransaction();
+				Zotero.Prefs.set('purge.tags', false);
 				return;
 			}
 			
@@ -393,6 +398,8 @@ Zotero.Tags = new function() {
 		finally {
 			Zotero.UnresponsiveScriptIndicator.enable();
 		}
+		
+		Zotero.Prefs.set('purge.tags', false);
 	}
 	
 	
diff --git a/chrome/content/zotero/xpcom/fulltext.js b/chrome/content/zotero/xpcom/fulltext.js
index 4825a07611..a01a8b62d3 100644
--- a/chrome/content/zotero/xpcom/fulltext.js
+++ b/chrome/content/zotero/xpcom/fulltext.js
@@ -634,10 +634,18 @@ Zotero.Fulltext = new function(){
 	
 	function clearItemWords(itemID){
 		Zotero.DB.beginTransaction();
-		Zotero.DB.query("DELETE FROM fulltextItems WHERE itemID=" + itemID);
-		Zotero.DB.query("DELETE FROM fulltextItemWords WHERE itemID=" + itemID);
+		var sql = "SELECT rowid FROM fulltextItems WHERE itemID=? LIMIT 1";
+		var indexed = Zotero.DB.valueQuery(sql, itemID);
+		if (indexed) {
+			Zotero.DB.query("DELETE FROM fulltextItems WHERE itemID=?", itemID);
+			Zotero.DB.query("DELETE FROM fulltextItemWords WHERE itemID=?", itemID);
+		}
 		Zotero.DB.commitTransaction();
 		
+		if (indexed) {
+			Zotero.Prefs.set('purge.fulltext', true);
+		}
+		
 		// Delete fulltext cache file if there is one
 		this.clearCacheFile(itemID);
 	}
@@ -933,10 +941,16 @@ Zotero.Fulltext = new function(){
 	*/
 	
 	
-	function purgeUnusedWords(){
+	function purgeUnusedWords() {
+		if (!Zotero.Prefs.get('purge.fulltext')) {
+			return;
+		}
+		
 		var sql = "DELETE FROM fulltextWords WHERE wordID NOT IN "
-			+ "(SELECT wordID FROM fulltextItemWords)";
+					+ "(SELECT wordID FROM fulltextItemWords)";
 		Zotero.DB.query(sql);
+		
+		Zotero.Prefs.set('purge.fulltext', false)
 	}
 	
 	
diff --git a/chrome/content/zotero/xpcom/itemTreeView.js b/chrome/content/zotero/xpcom/itemTreeView.js
index 651029a6dc..a9690dc8f7 100644
--- a/chrome/content/zotero/xpcom/itemTreeView.js
+++ b/chrome/content/zotero/xpcom/itemTreeView.js
@@ -155,6 +155,9 @@ Zotero.ItemTreeView.prototype.setTree = function(treebox)
 Zotero.ItemTreeView.prototype.refresh = function()
 {
 	Zotero.debug('Refreshing items list');
+	
+	var usiDisabled = Zotero.UnresponsiveScriptIndicator.disable();
+	
 	this._searchMode = this._itemGroup.isSearchMode();
 	
 	var oldRows = this.rowCount;
@@ -228,6 +231,10 @@ Zotero.ItemTreeView.prototype.refresh = function()
 	if (diff != 0) {
 		this._treebox.rowCountChanged(0, diff);
 	}
+	
+	if (usiDisabled) {
+		Zotero.UnresponsiveScriptIndicator.enable();
+	}
 }
 
 
diff --git a/chrome/content/zotero/xpcom/zotero.js b/chrome/content/zotero/xpcom/zotero.js
index 934e851c23..a3b6b256fa 100644
--- a/chrome/content/zotero/xpcom/zotero.js
+++ b/chrome/content/zotero/xpcom/zotero.js
@@ -970,6 +970,22 @@ var Zotero = new function(){
 	}
 	
 	
+	/*
+	 * Clear entries that no longer exist from various tables
+	 */
+	this.purgeDataObjects = function () {
+		Zotero.Creators.purge();
+		Zotero.Tags.purge();
+		Zotero.Fulltext.purgeUnusedWords();
+		Zotero.Items.purge();
+		
+		var ZU = new Zotero.Utilities;
+		if (Zotero.Sync.Storage.active && ZU.probability(10)) {
+			Zotero.Sync.Storage.purgeDeletedStorageFiles();
+		}
+	}
+	
+	
 	function reloadDataObjects() {
 		Zotero.Tags.reloadAll();
 		Zotero.Collections.reloadAll();
@@ -2103,7 +2119,9 @@ Zotero.UnresponsiveScriptIndicator = new function() {
 	 **/
 	function disable() {
 		// don't do anything if already disabled
-		if(_isDisabled) return;
+		if (_isDisabled) {
+			return false;
+		}
 		
 		var prefService = Components.classes["@mozilla.org/preferences-service;1"].
 		                  getService(Components.interfaces.nsIPrefBranch);
@@ -2111,6 +2129,7 @@ Zotero.UnresponsiveScriptIndicator = new function() {
 		prefService.setIntPref("dom.max_chrome_script_run_time", 0);
 		
 		_isDisabled = true;
+		return true;
 	}
 	 
 	/**
diff --git a/defaults/preferences/zotero.js b/defaults/preferences/zotero.js
index 94ae193588..93e8869a84 100644
--- a/defaults/preferences/zotero.js
+++ b/defaults/preferences/zotero.js
@@ -102,4 +102,10 @@ pref("extensions.zotero.sync.storage.deleteDelayDays", 30);
 
 // Proxy
 pref("extensions.zotero.proxies.autoRecognize", true);
-pref("extensions.zotero.proxies.transparent", true);
\ No newline at end of file
+pref("extensions.zotero.proxies.transparent", true);
+
+// Data layer purging
+pref("extensions.zotero.purge.creators", false);
+pref("extensions.zotero.purge.fulltext", false);
+pref("extensions.zotero.purge.items", false);
+pref("extensions.zotero.purge.tags", false);
\ No newline at end of file