Sandboxie Box Types and When to Use Each One

Sandboxie Plus does not treat every sandbox alike. When you create a new box, the wizard asks you to choose a type, and that single decision governs how tightly the box is sealed, what the programs inside it may read, and how well awkward software will behave once it is running. Most people accept the default and never look back, which is perfectly reasonable for casual browsing. Yet the other options exist for good reasons, and knowing what each one actually changes allows you to match the box to the job rather than hoping a single configuration suits everything.

This guide works through each type in turn, explains the settings that sit underneath them, and then turns to the features that can be layered on top of any box: snapshots, automatic deletion, network rules, encryption and RAM disk storage. It closes with practical scenarios, so that the theory has somewhere to land.

Why Sandboxie box types matter

Every box in Sandboxie rests on the same foundation. The kernel driver, SbieDrv.sys, starts sandboxed processes with a heavily restricted token and enforces rules on the system calls they make. The service, SbieSvc.exe, carries out privileged tasks on their behalf, and SbieDll.dll is injected into each sandboxed process to virtualise the file system and registry. Writes are redirected into the box using a copy-on-write approach: a program reading a file it has never touched sees the original, but the moment it writes, a copy is created inside the sandbox and used from then on.

The Sandboxie box types adjust this foundation in different directions. Some tighten it, removing administrative rights and narrowing the system calls a program may make. One hides your personal data from the boxed program entirely. Another deliberately loosens the security layer to improve compatibility while keeping the file and registry virtualisation intact. None of them changes the basic mechanics; they change the rules the mechanics enforce.

It is worth stating plainly that only the Standard type is available on the free tier. Security Hardened, Privacy Enhanced and App Compartment boxes all require a supporter certificate. That is not a reason to skip reading about them, because understanding what the Standard box does not do is the best way to judge whether it is enough for you.

Standard Isolation: the default box

The Standard Isolation box is what you get when you install Sandboxie and open DefaultBox for the first time. Programs launched in it run under the restricted token, their writes land in the sandbox folder rather than on the real disk, and their registry changes go into a private hive mounted under HKEY_USERS. Inter-process communication objects such as events, mutexes and RPC ports are given a separate namespace for each box, which is why you can run the same program inside and outside a sandbox at the same time without the two copies colliding.

What the Standard box does not do is prevent reading. A program inside it can, by default, read most of the files on your system. It cannot alter them, and it cannot leave anything behind once the box is emptied, but it can see them. For a browser visiting unfamiliar sites, or a utility you want to try without letting its installer scatter files across the system, that trade-off is usually acceptable. For software you trust less, or for work that touches sensitive documents, it may not be.

Where Standard boxes fit well

• Everyday browsing, particularly when you want cookies, cache and downloads discarded afterwards.
• Trying out an installer to see what it would change, then deleting the box.
• Running two instances of a program that normally refuses to start twice.
• Keeping a cluttered application's temporary files out of your real profile.

Security Hardened boxes and their four settings

The Security Hardened type, added in the 1.3.0 release, is enabled by a single switch, UseSecurityMode=y. That switch is shorthand for four separate settings, each of which closes a different avenue of attack. It helps to understand them individually, because the same settings can be applied by hand in the configuration file where the edition you use supports it.

[HardenedBox]
UseSecurityMode=y
# which implies:
DropAdminRights=y
RestrictDevices=y
SysCallLockDown=y
UseRuleSpecificity=y

DropAdminRights

Even if you start a program from an elevated account, this setting strips administrative rights from everything running in the box. Installers that insist on elevation may complain, but malicious code loses the ability to perform actions that only administrators can carry out. It is the simplest of the four and arguably the most valuable on its own.

RestrictDevices

Programs talk to hardware and to many system components through device objects. Restricting access to these narrows the surface a hostile process can probe. Ordinary applications rarely notice the difference, though software that expects direct hardware access will not work under it.

SysCallLockDown

Sandboxie routes selected native system call stubs through its driver, which applies its rules before passing them on. Some programs attempt to bypass such hooks with direct system calls; those calls still run under the restricted token, but locking down the permitted system calls further reduces what an escape attempt can achieve. This is where the hardened mode earns its name.

UseRuleSpecificity

Access rules in Sandboxie come in several forms, including OpenFilePath, ReadFilePath, WriteFilePath and ClosedFilePath. When rules overlap, the question is which one wins. Rule specificity resolves this by giving precedence to the more precisely targeted rule, which lets you close a broad area while opening a narrow exception within it, and makes the resulting behaviour predictable.

Privacy Enhanced, App Compartment and combined presets

Privacy Enhanced boxes

The Privacy Enhanced type, switched on by UsePrivacyMode=y, answers the weakness of the Standard box described earlier. Programs inside it cannot read your user data. Where they would otherwise see your documents, pictures and profile folders, they find empty locations instead. The program can still create files of its own inside the box, and those behave normally, but the contents of your real profile are hidden from view.

This matters more than many people assume. A browser extension, a free converter or an unfamiliar tool may never try to damage anything, yet still have reasons to look around. In a Standard box it could read a spreadsheet in your Documents folder; in a Privacy Enhanced box it simply finds nothing there. The trade-off is that a program which genuinely needs one of your files cannot reach it unless you open a specific path with an access rule, or move the file into a location the box can see.

App Compartment boxes

App Compartment arrived with the 1.0.0 release and runs in the opposite direction from the hardened types. Its setting, NoSecurityIsolation=y, disables the token-based security isolation while keeping the file and registry virtualisation. Programs run with ordinary rights, which removes a whole class of compatibility problems, but their changes are still captured inside the box.

The result is a tidy container rather than a security barrier. It is ideal for portable-style use of trusted software: keeping a second configuration of an application apart from the first, preventing a program from cluttering the registry, or running a tool whose sandboxed behaviour is unreliable under the restricted token. It is not suitable for anything you distrust, because the protections that would contain hostile code have been switched off on purpose.

Combined presets

The types are not strictly exclusive. Privacy and security settings can be combined, and when both are active the box is marked with a red icon in SandMan, which makes it easy to recognise the most tightly sealed boxes at a glance. App Compartment can also be paired with data protection, giving you the compatibility of the compartment while still preventing the program from reading your personal files. That combination suits trusted but nosy software well: an application you need to run with normal rights, but whose access to your profile you would rather limit.

Choosing between Sandboxie box types

The table below summarises how the Sandboxie box types differ in practice. It is a guide rather than a rulebook; individual programs sometimes behave differently from what their category would suggest.

A simple rule of thumb follows from this. The less you trust a program, the further up the security column you should move. The more a program struggles to run, the further towards App Compartment you can move, but only if you trust it.

Features you can layer onto any box

Beyond the type itself, several features shape how a box behaves day to day. Some are free and some require a certificate or the Advanced Feature Pack.

Snapshots

Snapshots are available on the free tier. They record the state of a box so that you can return to it later. If you have set up a browser exactly as you like it, with extensions installed and settings adjusted, a snapshot lets you browse freely and then roll back to that clean, configured state rather than starting again from nothing. They are equally handy before testing an update to a sandboxed program: take a snapshot, try the update, and revert if it misbehaves.

Automatic deletion

A box can be set to empty itself automatically once its programs have finished. This turns any box into a disposable environment without requiring you to remember to clear it. Bear in mind that anything you have not recovered is lost when the box is deleted, so pair automatic deletion with Immediate Recovery if you expect to download files you want to keep. Recovered files are copies leaving the box, so they deserve a scan before you open them.

Network rules

Sandboxie can apply network restrictions through the Windows Filtering Platform, and this support is included on the free tier. You can block internet access for a box altogether, which is useful when testing software you suspect of phoning home. The 1.17.4 release also introduced a BlockLocalLoop=y option for restricting traffic to the local loopback interface.

Encrypted boxes

The 1.11 series introduced encrypted boxes, which store their contents in an encrypted container. Nothing a boxed program writes can be read from the disk without the key, which is valuable on a laptop that might be lost or on a machine shared with others. Encrypted boxes can be mounted and unmounted from the command line with Start.exe using the /mount and /unmount switches together with /key. Sandbox encryption belongs to the Advanced Feature Pack, which is required in addition to a certificate, though Contributor and Eternal certificates include it.

RAM disk boxes

Also introduced in the 1.11 series, RAM disk support places a box's contents in memory rather than on the physical disk. When the machine is shut down, the contents vanish. This makes a RAM disk box a natural choice for work that should leave no trace on storage, and it can be quicker for programs that write many small temporary files. RAM disk support requires a certificate.

Practical scenarios for each type

Abstract descriptions only go so far. The following situations illustrate how the choice tends to play out.

• Opening an unfamiliar download. A Security Hardened box combined with privacy settings is the strongest choice Sandboxie offers. Administrative rights are dropped, system calls are restricted and your documents are invisible. Add a network block if you would rather the program could not contact anything.
• Daily browsing. A Standard box with automatic deletion and Immediate Recovery for the Downloads folder is a sensible, free configuration. A snapshot taken after setting up extensions saves time later.
• Online banking or private correspondence. A Privacy Enhanced box keeps the browser from seeing anything else in your profile, and an encrypted box protects the stored session data if the device leaves your hands.
• Running two configurations of a trusted tool. App Compartment keeps each configuration separate without the compatibility issues that the restricted token can cause.
• A trusted program that wants too much access. App Compartment with data protection lets it run normally while keeping it away from your personal files.
• Short-lived research sessions. A RAM disk box ensures that nothing written during the session reaches the physical disk.

Frequently Asked Questions

Conclusion

The box type is the most consequential choice you make when setting up Sandboxie, yet it is often the one given least thought. Standard Isolation handles a great deal of everyday work, and it costs nothing. The paid types each address a specific shortcoming: Security Hardened narrows what boxed code can do, Privacy Enhanced stops it from reading what it has no business reading, and App Compartment trades security for compatibility when the software is trustworthy but temperamental. Understanding those trade-offs is far more useful than memorising a list of settings.

The supporting features then let you fine-tune each box for its purpose. Snapshots preserve a known good state, automatic deletion keeps disposable boxes genuinely disposable, network rules cut off unwanted traffic, and encryption or RAM disk storage controls what remains on the disk. Start with one box per kind of task, give each the type that fits its level of trust, and adjust from there as you learn how your own programs behave.