diff --git a/plugins/c9.ide.download/download.js b/plugins/c9.ide.download/download.js
index dd6a585f..ab8e5280 100644
--- a/plugins/c9.ide.download/download.js
+++ b/plugins/c9.ide.download/download.js
@@ -91,24 +91,30 @@ define(function(require, exports, module) {
         }
 
         function downloadProject() {
-            vfs.download("/", info.getWorkspace().name + getArchiveFileExtension());
+            vfs.download("/", makeArchiveFilename(info.getWorkspace().name));
         }
 
         function downloadPaths(paths) {
-            vfs.download(paths, info.getWorkspace().name + getArchiveFileExtension());
+            var lastPart = paths[0].match(/([^\/]*)\/?$/)[1];
+            var filename = lastPart ? (lastPart + "[+" + (paths.length - 1) + "]") : info.getWorkspace().name;
+            vfs.download(paths, makeArchiveFilename(filename));
         }
 
         function downloadFolder(path) {
             var withTrailingSlash = path.replace(/\/*$/, "/");
             var parts = withTrailingSlash.split("/");
-            var lastPart = parts[parts.length - 2];
-            vfs.download(withTrailingSlash, lastPart + getArchiveFileExtension());
+            var folderName = parts[parts.length - 2];
+            vfs.download(withTrailingSlash, makeArchiveFilename(folderName));
         }
 
         function downloadFile(path) {
             vfs.download(path.replace(/\/*$/, ""), null, true);
         }
 
+        function makeArchiveFilename(filename) {
+            return filename + getArchiveFileExtension();
+        }
+
         function getArchiveFileExtension() {
             var downloadFilesAs = settings.get(SETTING_PATH);
             if (downloadFilesAs === 'auto' || !downloadFilesAs) {
diff --git a/plugins/c9.vfs.client/vfs_client.js b/plugins/c9.vfs.client/vfs_client.js
index 93557f30..9badea1b 100644
--- a/plugins/c9.vfs.client/vfs_client.js
+++ b/plugins/c9.vfs.client/vfs_client.js
@@ -198,7 +198,8 @@ define(function(require, exports, module) {
             }
             window.open(vfsUrl(path) + extraPaths
                 + "?download" 
-                + (filename ? "=" + escape(filename) : "")
+                // Escape '+', otherwise it gets interpreted as a space.
+                + (filename ? "=" + escape(filename) : "").replace(/\+/g, "%2B")
                 + (isfile ? "&isfile=1" : ""));
         }
 
diff --git a/plugins/c9.vfs.server/download.js b/plugins/c9.vfs.server/download.js
index b1dbea6f..b259713e 100644
--- a/plugins/c9.vfs.server/download.js
+++ b/plugins/c9.vfs.server/download.js
@@ -44,11 +44,11 @@ define(function(require, exports, module) {
                     filename += (paths.length > 1 ? "[+" + (paths.length - 1) + "]"  : "") + ".tar.gz";
                 }
             }
-            var filenameHeader = "attachment; filename*=utf-8''" + encodeURIComponent(filename);
+            var filenameHeader = "attachment; filename*=utf-8''" + escape(filename);
 
-            var process;
+            var proc;
             req.on("close", function() {
-                if (process) process.kill();
+                if (proc) proc.kill();
             });
             
             if (req.uri.query.isfile) {
@@ -113,24 +113,26 @@ define(function(require, exports, module) {
                 paths.forEach(function(path) {
                     if (!path) return;
                     path = Path.relative(cwd, path);
-                    // tar misinterprets the Windows path separator as an escape sequence, so use forward slash.
-                    if (Path.sep === '\\') {
-                        path = path.replace(/\\/g, '/');
+                    if (process.platform == "win32") {
+                        // Quote the path to escape unusual characters and spaces.
+                        // NB: Double quotes are illegal within the actual path on Windows.
+                        path = '"' + path.replace(/"/g, "") + '"';
                     }
                     args.push(path);
                 });
 
                 vfs.spawn(executable, {
                     args: args,
-                    cwd: cwd
+                    cwd: cwd,
+                    windowsVerbatimArguments: true // Prevents Node from escaping the double quotes added above.
                 }, function (err, meta) {
                     if (err)
                         return next(err);
 
-                    process = meta.process;
+                    proc = meta.process;
 
                     // once we receive data on stdout pipe it to the response
-                    process.stdout.once("data", function (data) {
+                    proc.stdout.once("data", function (data) {
                         if (res.headerSent)
                             return;
                             
@@ -139,15 +141,15 @@ define(function(require, exports, module) {
                             "Content-Disposition": filenameHeader
                         });
                         res.write(data);
-                        process.stdout.pipe(res);
+                        proc.stdout.pipe(res);
                     });
             
                     var stderr = "";
-                    process.stderr.on("data", function (data) {
+                    proc.stderr.on("data", function (data) {
                         stderr += data;
                     });
 
-                    process.on("exit", function(code, signal) {
+                    proc.on("exit", function(code, signal) {
                         if (res.headerSent)
                             return;