diff --git a/src/storage/filesystem.js b/src/storage/filesystem.js
index ea2b0eea5..d8a11781a 100644
--- a/src/storage/filesystem.js
+++ b/src/storage/filesystem.js
@@ -214,7 +214,7 @@ async function copyInternal(config, fromPath, toPath, options, progressCallback)
         if (!safe.fs.writeFileSync(identityFilePath, `${config.mountOptions.privateKey}\n`, { mode: 0o600 })) throw new BoxError(BoxError.FS_ERROR, `Could not write temporary private key: ${safe.error.message}`);
 
         const sshOptions = [ '-o', '"StrictHostKeyChecking no"', '-i', identityFilePath, '-p', config.mountOptions.port, `${config.mountOptions.user}@${config.mountOptions.host}` ];
-        const sshArgs = sshOptions.concat([ 'cp', cpOptions, path.join(config.prefix, fromPath), path.join(config.prefix, toPath) ]);
+        const sshArgs = sshOptions.concat([ 'cp', cpOptions, path.join(config.prefix ?? '', fromPath), path.join(config.prefix ?? '', toPath) ]);
         const [remoteCopyError] = await safe(shell.spawn('ssh', sshArgs, { shell: true }));
         safe.fs.unlinkSync(identityFilePath);
         if (!remoteCopyError) return;
@@ -273,7 +273,7 @@ async function removeDir(config, limits, remotePathPrefix, progressCallback) {
         const identityFilePath = path.join(paths.SSHFS_KEYS_DIR, `identity_file_${path.basename(config._managedMountPath)}`);
 
         const sshOptions = [ '-o', '"StrictHostKeyChecking no"', '-i', identityFilePath, '-p', config.mountOptions.port, `${config.mountOptions.user}@${config.mountOptions.host}` ];
-        const sshArgs = sshOptions.concat([ 'rm', '-rf', path.join(config.prefix, remotePathPrefix) ]);
+        const sshArgs = sshOptions.concat([ 'rm', '-rf', path.join(config.prefix ?? '', remotePathPrefix) ]);
         const [remoteRmError] = await safe(shell.spawn('ssh', sshArgs, { shell: true }));
         if (!remoteRmError) return;
         if (remoteRmError.code === 255) throw new BoxError(BoxError.EXTERNAL_ERROR, `SSH connection error: ${remoteRmError.message}`); // do not attempt fallback copy for ssh errors
@@ -352,6 +352,8 @@ async function verifyConfig({ id, provider, config }) {
             if (path.isAbsolute(config.prefix)) throw new BoxError(BoxError.BAD_FIELD, 'prefix must be a relative path');
             if (path.normalize(config.prefix) !== config.prefix) throw new BoxError(BoxError.BAD_FIELD, 'prefix must contain a normalized relative path');
         }
+    } else {
+        config.prefix = '';
     }
 
     if (provider === mounts.MOUNT_TYPE_FILESYSTEM) {