diff --git a/core/dropbox.js b/core/dropbox.js
index bdd384e..4cd5499 100644
--- a/core/dropbox.js
+++ b/core/dropbox.js
@@ -17,11 +17,15 @@ const Dropbox = {
     /**
      * Initialize the Dropbox object by loading values from Zotero.ZeNotes.Prefs.
      */
-    init() {
+    async init() {
         this.accessToken = Zotero.ZeNotes.Prefs.getb('dropbox-access-token', '');
         this.refreshToken = Zotero.ZeNotes.Prefs.getb('dropbox-refresh-token', '');
         this.clientId = Zotero.ZeNotes.Prefs.getb('dropbox-client-id', '');
         this.clientSecret = Zotero.ZeNotes.Prefs.getb('dropbox-client-secret', '');
+		if(this.accessToken=="")
+		{
+			await this.refresh();
+		}
     },
 
     /**
@@ -80,7 +84,6 @@ const Dropbox = {
 			});
 
 			if (response.status === 401) {
-				// console.log('Access token expired, refreshing...');
 				await this.refresh();
 				return this.upload(filePath, fileContent, callback);
 			}
diff --git a/core/nsync.js b/core/nsync.js
index 6ab70ad..c60b7db 100644
--- a/core/nsync.js
+++ b/core/nsync.js
@@ -81,18 +81,19 @@ function update() {
 		var activecollection = Zotero.getActiveZoteroPane().getSelectedCollection().name;
 		var outfile = Zotero.File.pathToFile(Zotero.getTempDirectory().path+"\\zenotes-import.zip").path;
 		var destfilename = Zotero.File.pathToFile(Zotero.getTempDirectory().path+"\\zenotes-import").path;
-		Dropbox.init();
-		return Dropbox.download(activecollection+".zip", function(data, hash){
-			Zotero.File.putContentsAsync(outfile, data).then(e=>{
-				unzip(outfile, destfilename, 
-					function(){Zotero_File_Interface.Progress.show("Unzipping file ...");},
-					function(m){Zotero_File_Interface.Progress.show(m);},
-					function(){
-						Zotero_File_Interface.Progress.close();
-						callback(destfilename+"\\zenotes-export.rdf", hash);
-					},
-				);
-			})
+		Dropbox.init().then(token=> {
+			return Dropbox.download(activecollection+".zip", function(data, hash){
+				Zotero.File.putContentsAsync(outfile, data).then(e=>{
+					unzip(outfile, destfilename, 
+						function(){Zotero_File_Interface.Progress.show("Unzipping file ...");},
+						function(m){Zotero_File_Interface.Progress.show(m);},
+						function(){
+							Zotero_File_Interface.Progress.close();
+							callback(destfilename+"\\zenotes-export.rdf", hash);
+						},
+					);
+				})
+			});
 		});
 	}
 	
@@ -100,10 +101,10 @@ function update() {
 	{
 		var target = Zotero.ZeNotes.Prefs.get('dropbox-target-user', 'allusers');
 		var filename = Zotero.getActiveZoteroPane().getSelectedCollection().name;
-		Dropbox.init();
-		
-		var fn = "/"+target+"/"+filename+".zip";
-		Dropbox.upload(fn, contents, callback);
+		Dropbox.init().then(token=>{
+			var fn = "/"+target+"/"+filename+".zip";
+			Dropbox.upload(fn, contents, callback);
+		})
 	}
 	
 	delay = function(ms)
@@ -212,7 +213,7 @@ function update() {
 
 NSync = {
 	export()
-	{
+	{	
 		var zp = Zotero.getActiveZoteroPane();
 		var collection = zp.getSelectedCollection();
 		if(!collection)
@@ -249,7 +250,6 @@ NSync = {
 	
 	async beforeimport(activecollection, hash)
 	{
-		
 		Zotero_File_Interface.Progress.show("Importing all items to Zotero ...");
 		Zotero.ZeNotes.DBPrefs.set("zenotes.nsync.collectionhash:"+activecollection, hash);
 	},
@@ -269,50 +269,52 @@ NSync = {
 		}
 		var activecollection = collection.name;
 		var username = Zotero.Prefs.get("extensions.zotero.sync.server.username", true);
-		Dropbox.init();
-		Dropbox.list(username).then(async list=>{
-			let dataexists = list.map(a=>{return a.name.replace(".zip", "")}).includes(activecollection);
-			if(dataexists)
-			{
-				let current_hash = await Zotero.ZeNotes.DBPrefs.get("zenotes.nsync.collectionhash:"+activecollection);
-				let file = list.filter(f => f.name === activecollection+".zip")[0];
-								
-				if(file.content_hash!=current_hash)
+		Dropbox.init().then(token=>{
+			Dropbox.list(username).then(async list=>{
+				let dataexists = list.map(a=>{return a.name.replace(".zip", "")}).includes(activecollection);
+				if(dataexists)
 				{
-					return download(async function(localfilename, hash){
-						Zotero_File_Interface.Progress.show("Importing items to Zotero ...");
-						return await Zotero_File_Interface.importFile({
-							file: localfilename,
-							recreateStructure: false,
-							createNewCollection: false,
-							addToLibraryRoot: false,
-							linkFiles: false,
-							onBeforeImport: async function(){return NSync.beforeimport(activecollection, hash)},
-						}).then(e=>{
-							NSync.annotations(e).then(transfered=>{
-								if(transfered)
-								{
-									Zotero_File_Interface.Progress.close();
-									alert("All items imported!");
-								}
+					let current_hash = await Zotero.ZeNotes.DBPrefs.get("zenotes.nsync.collectionhash:"+activecollection);
+					let file = list.filter(f => f.name === activecollection+".zip")[0];
+									
+					if(file.content_hash!=current_hash)
+					{
+						return download(async function(localfilename, hash){
+							Zotero_File_Interface.Progress.show("Importing items to Zotero ...");
+							return await Zotero_File_Interface.importFile({
+								file: localfilename,
+								recreateStructure: false,
+								createNewCollection: false,
+								addToLibraryRoot: false,
+								linkFiles: false,
+								onBeforeImport: async function(){return NSync.beforeimport(activecollection, hash)},
+							}).then(e=>{
+								NSync.annotations(e).then(transfered=>{
+									if(transfered)
+									{
+										Zotero_File_Interface.Progress.close();
+										alert("All items imported!");
+									}
+								})
 							})
-						})
-					});
+						});
+					}
+					else
+					{
+						if(confirm("You have already downloaded this file! Do you want to force download?"))
+						{
+							Zotero.ZeNotes.DBPrefs.set("zenotes.nsync.collectionhash:"+activecollection, "");
+							NSync.import();
+						};
+					}
 				}
 				else
 				{
-					if(confirm("You have already downloaded this file! Do you want to force download?"))
-					{
-						Zotero.ZeNotes.DBPrefs.set("zenotes.nsync.collectionhash:"+activecollection, "");
-						NSync.import();
-					};
+					alert("You do not have data on \""+activecollection+"\" on the server!");
 				}
-			}
-			else
-			{
-				alert("You do not have data on \""+activecollection+"\" on the server!");
-			}
-		})
+			})
+		});
+		
 	},
 	
 	async annotations(imported)
diff --git a/install.rdf b/install.rdf
index 016d6ab..9a5df36 100644
--- a/install.rdf
+++ b/install.rdf
@@ -5,7 +5,7 @@
     <Description about="urn:mozilla:install-manifest">
         <em:id>zenotes@alefa.net</em:id>
         <em:name>ZeNotes</em:name>
-        <em:version>0.8.9</em:version>
+        <em:version>0.9.0</em:version>
         <em:multiprocessCompatible>true</em:multiprocessCompatible>
         <em:updateURL>https://raw.githubusercontent.com/frianasoa/zenotes/main/zenote-update.json</em:updateURL>
         <em:homepageURL>https://github.com/frianasoa/zenotes</em:homepageURL>
diff --git a/manifest.json b/manifest.json
index e63b3a1..e1995e1 100644
--- a/manifest.json
+++ b/manifest.json
@@ -1,7 +1,7 @@
 {
     "manifest_version": 2,
     "name": "Ze Notes",
-    "version": "0.8.9",
+    "version": "0.9.0",
     "description": "Advanced notes manager",
     "homepage_url": "https://github.com/frianasoa/zenotes",
     "author": "Fanantenana Rianasoa Andriariniaina",
diff --git a/zenote-update.json b/zenote-update.json
index 18ab73c..0b03774 100644
--- a/zenote-update.json
+++ b/zenote-update.json
@@ -3,9 +3,9 @@
     "zenotes@alefa.net": {
       "updates": [
         {
-          "version": "0.8.9",
-          "update_link": "https://github.com/frianasoa/Ze-Notes/releases/download/v0.8.9/zenotes-v0.8.9.xpi",
-          "update_hash": "sha256:b050c3bb68f553d52fbf037daa408912ffc3735ecf677b085762aa20dfcd477b",
+          "version": "0.9.0",
+          "update_link": "https://github.com/frianasoa/Ze-Notes/releases/download/v0.9.0/zenotes-v0.9.0.xpi",
+          "update_hash": "sha256:001441b3455fb9c59f67955ae71c00c7508fdfe118cbf370abbca082a67d6550",
           "applications": {
             "gecko": {
               "strict_min_version": "60.0"
diff --git a/zenote-update.rdf b/zenote-update.rdf
index bf8e69b..8c326a6 100644
--- a/zenote-update.rdf
+++ b/zenote-update.rdf
@@ -5,13 +5,13 @@
             <rdf:Seq>
                 <rdf:li>
                     <rdf:Description>
-                        <ns1:version>0.8.9</ns1:version>
+                        <ns1:version>0.9.0</ns1:version>
                         <ns1:targetApplication>
                             <rdf:Description>
                                 <ns1:id>zotero@chnm.gmu.edu</ns1:id>
                                 <ns1:minVersion>5.0.0</ns1:minVersion>
                                 <ns1:maxVersion>6.*</ns1:maxVersion>
-                                <ns1:updateLink>https://github.com/frianasoa/Ze-Notes/releases/download/v0.8.9/zenotes-v0.8.9.xpi</ns1:updateLink>
+                                <ns1:updateLink>https://github.com/frianasoa/Ze-Notes/releases/download/v0.9.0/zenotes-v0.9.0.xpi</ns1:updateLink>
                             </rdf:Description>
                         </ns1:targetApplication> 
 
@@ -20,7 +20,7 @@
                                 <ns1:id>juris-m@juris-m.github.io</ns1:id>
                                 <ns1:minVersion>4.999</ns1:minVersion>
                                 <ns1:maxVersion>6.*</ns1:maxVersion>
-                                <ns1:updateLink>https://github.com/frianasoa/Ze-Notes/releases/download/v0.8.9/zenotes-v0.8.9.xpi</ns1:updateLink>
+                                <ns1:updateLink>https://github.com/frianasoa/Ze-Notes/releases/download/v0.9.0/zenotes-v0.9.0.xpi</ns1:updateLink>
                             </rdf:Description>
                         </ns1:targetApplication>