The short answer: A folder lock app stops other people opening the files in a folder. Some only hide the folder, some move your files into a password-protected vault, and some encrypt the folder itself. ZapLock is the third kind, without the password: it encrypts the folder in place with AES-256-GCM, keeps its name and path, and opens it with a ZapQR sign-in. Each folder's key is split between your device and our service, so we can't open your folders, and signing in on a new device hands over no key.
Hidden, vaulted or encrypted in place
Most "folder lock" tools fall into one of these. Only encryption protects the files if someone copies the disk, plugs it into another computer, or gets at your cloud account.
Hide it
Batch-file "lockers", hidden attributes and app locks. They keep a folder out of sight on one device. The files underneath aren't encrypted, so another app, another account or another computer can read them.
Not real protectionVault it behind a password
Password lockers, encrypted disk images and zip archives. Your files move into a container you open with a password. Strong if the password is, but forget it and the files are usually gone, and everyone you share with needs the same password.
Works, with a password to keepEncrypt it in place
ZapLock encrypts the files inside the folder you already have. It keeps its name and path, so aliases, backups and sync clients keep working. You open it by signing in, and each person you share with gets their own access.
ZapLockSame folder, same place. Unreadable without you.
Here's a folder in Google Drive before and after ZapLock locks it.
Google Drive/
└── Clients/
├── 2026-returns.pdf
├── passports/
└── engagement.docx
Anyone with the drive, the laptop or
your Google account can read these.
Google Drive/ └── Clients/ ← same name, same path ├── zaplock.json ├── recipients/ └── d/ (encrypted) Opens with your ZapQR sign-in.
How to lock a folder on each platform
Each guide covers what your device can already do on its own, where that falls short, and the ZapLock steps.
ZapLock next to the usual ways to lock a folder
| ZapLock | Password locker apps | Built-in tools | |
|---|---|---|---|
| How you open it | ZapQR sign-in, plus an optional Face ID, fingerprint, Windows Hello or phone check | A password or PIN | Varies: a disk-image password, your Windows account, your phone's screen lock |
| Forgot the password | There isn't one to forget | Usually the files are gone | Usually the files are gone |
| Where files live | The folder you already have, in place | Inside the app's locker or vault | A disk image, an archive, or a special app folder |
| Cloud folders | Dropbox, Google Drive, iCloud Drive, OneDrive | Depends on the app | Mostly local only |
| Same folder on every device | Mac, Windows, iPhone, iPad, Android | Depends on the app | One platform each |
| Share and take back access | Per person, by email. Revoke any time | Share the password, then change it | Rarely |
| Works fully offline | No. A new unlock needs our service | Usually | Yes |
"Password locker apps" and "built-in tools" describe the category, not every product in it. See each platform guide for specifics and sources.
"Folder lock" is used here only to describe a kind of app. Folder Lock is a registered trademark of its owner; ZapLock isn't affiliated with the Folder Lock product or its maker.
How to lock a folder with ZapLock
The same four steps on every platform. The platform guides show exactly where each button is.
Install ZapLock and sign in
Get it from the Mac App Store, Microsoft Store, App Store or Google Play, and sign in with a free ZapQR account. No password to make up.
Sign in on a second device
Before you lock anything important, sign in on a second phone or computer too. Each device holds its own share of a folder's key, so a second device means losing one doesn't lock you out.
Pick the folder and lock it
Choose the folder in ZapLock, or right-click it in Finder or File Explorer. The files are encrypted where they are. The folder keeps its name and path.
Open it with your sign-in
Unlock it in ZapLock with your sign-in, plus Face ID, a fingerprint or Windows Hello if you've turned that on. It locks again when you're done, when you quit, or after the idle time you set.
What ZapLock won't do
Worth knowing up front, so nothing surprises you later.
- You need a free ZapQR account. That sign-in is what replaces the password.
- Opening a folder needs a connection to our service, which releases its half of the key. A new unlock waits until you're back online.
- If a folder's key lives on only one device and you lose that device, the folder can't be opened. Sign in on a second device before you lock anything you can't lose.
- No Linux, and the apps aren't open source.
- Sync services keep version history. If plain copies were ever synced, your provider may still hold them.
Folder lock FAQ
What is a folder lock app?
A folder lock app stops other people opening the files in a folder. Some only hide the folder, some move files into a password-protected vault, and some encrypt the folder where it sits. Only encryption keeps the files safe if someone copies the disk, plugs it into another computer or gets into your cloud account. ZapLock encrypts in place and opens with a sign-in instead of a password.
Can I lock a folder without a password?
Yes. A ZapLock folder opens with your free ZapQR sign-in, and you can add Face ID, Touch ID, a fingerprint, Windows Hello or approval on your phone. Each folder's key is split between your device and our service, and neither half opens anything alone.
Is there a free folder lock app?
Yes. ZapLock's Free plan locks one folder for good on Mac, Windows, iPhone, iPad and Android, and opening folders is always free. Personal is $49 a year on the web for unlimited folders and sharing with up to 3 people. Your device's built-in tools are free too, with limits covered in the Mac, Windows, iPhone and Android guides.
Does a locked folder open on my other devices?
Yes. Every ZapLock app uses the same folder format, so a folder you lock on a Mac opens on a Windows PC, an iPhone, an iPad or an Android phone. The other device needs to reach the folder, for example through Dropbox, Google Drive, iCloud Drive or a USB drive, and to have its key, which one of your devices hands it the first time.
What happens if I forget the password to a folder lock?
With most password lockers, the files are gone. Google's help page for Safe folder in Files by Google says it plainly: if you forget your PIN or pattern, you can't access your files. ZapLock has no folder password to forget, because you open folders by signing in.
What if I lose my phone or laptop?
Sign in on another device and end the lost device's session. Folders it had open lock themselves once it gets the message, and it can't get a key from us again. If the lost device was the only one holding a folder's key, that folder can't be opened, which is why you should sign in on a second device before you lock anything important.
Can ZapLock or DaSecure open my files?
No. Files are encrypted with AES-256-GCM on your device, and each folder's key is split in two. Our server holds one half, and that half alone decrypts nothing. Your files, their names and a whole key never leave your device.
Does a locked folder still sync to Dropbox, Google Drive, iCloud Drive or OneDrive?
Yes. The folder stays where it is, so your sync client keeps syncing it, but only encrypted files upload. Sync services keep version history, so if plain copies were synced before you locked the folder, clear that history with your provider if it matters to you.
Is there a folder lock for a small business team?
Yes. ZapLock Team is $9 per seat a month, with a 3-seat minimum. Folders belong to the team, and when someone leaves, one removal deletes their share of every team folder's key, so their next unlock is refused. See offboarding encrypted folders.
Lock your first folder in a minute.
Free for one folder, for good. On Mac, Windows, iPhone, iPad and Android.
Built-in options checked 22 October 2026 against: Files by Google: Safe folder.