diff --git a/src/storage/sshfs.js b/src/storage/sshfs.js
index 82494e519..c69065c37 100644
--- a/src/storage/sshfs.js
+++ b/src/storage/sshfs.js
@@ -103,10 +103,25 @@ function testConfig(apiConfig, callback) {
 
     // TODO check fstab entry
     // TODO check mountpoint
-    // TODO check we can stat backup dir
-    // TODO check backup dir is dir
-    // TODO check we can create 'snapshot' folder
-    // TODO check we can write to backup dir (create and remove test file)
+
+    const backupPath = path.join(apiConfig.mountPoint, apiConfig.prefix);
+
+    const stat = safe.fs.statSync(backupPath);
+    if (!stat) return callback(new BoxError(BoxError.BAD_FIELD, 'Directory does not exist or cannot be accessed: ' + safe.error.message), { field: 'prefix' });
+    if (!stat.isDirectory()) return callback(new BoxError(BoxError.BAD_FIELD, 'Backup location is not a directory', { field: 'prefix' }));
+
+    if (!safe.fs.mkdirSync(path.join(backupPath, 'snapshot')) && safe.error.code !== 'EEXIST') {
+        if (safe.error && safe.error.code === 'EACCES') return callback(new BoxError(BoxError.BAD_FIELD, `Access denied. Run "chown yellowtent:yellowtent ${backupPath}" on the server`, { field: 'prefix' }));
+        return callback(new BoxError(BoxError.BAD_FIELD, safe.error.message, { field: 'prefix' }));
+    }
+
+    if (!safe.fs.writeFileSync(path.join(backupPath, 'cloudron-testfile'), 'testcontent')) {
+        return callback(new BoxError(BoxError.BAD_FIELD, `Unable to create test file as 'yellowtent' user in ${backupPath}: ${safe.error.message}. Check dir/mount permissions`, { field: 'prefix' }));
+    }
+
+    if (!safe.fs.unlinkSync(path.join(backupPath, 'cloudron-testfile'))) {
+        return callback(new BoxError(BoxError.BAD_FIELD, `Unable to remove test file as 'yellowtent' user in ${backupPath}: ${safe.error.message}. Check dir/mount permissions`, { field: 'prefix' }));
+    }
 
     callback(null);
 }