Sandboxie: one core shared by two editions, and a Plus feature list that keeps growing

Two editions, identical core, and the interface is the whole difference

The fork publishes Sandboxie twice, and the relationship between the two builds is stated plainly. Plus and Classic share the same core components, which means they have the same level of security and compatibility. What differs is the availability of features in the user interface. Plus is a modern Qt based interface that supports all the features added since the project went open source. Classic is the old MFC based interface, described as no longer developed, so it has no native support for the Plus features. The escape hatch Classic users are given is manual work: some missing features can be configured by hand in `Sandboxie.ini`, or replaced with custom scripts, and the project's own judgement is that Classic is not recommended for users who want to explore the latest security options. That is the alternative worth weighing before you install anything, and it is not a close one. Licences follow the split, with `LICENSE.Plus` and `LICENSE.Classic` sitting at the root, so read the one that matches your download rather than assuming the GPL-3.0 label covers both identically.

The isolation boundary is drives, mapped drives, and the registry

What the software does is narrow and checkable. It is sandbox based isolation software for Windows NT based operating systems, and it creates an environment where applications can be run or installed without permanently modifying local and mapped drives or the Windows registry. The stated purpose is controlled testing of untrusted programs and web surfing. You can create what the README calls virtually unlimited sandboxes, run them alone or simultaneously, and inside a single box run as many programs as you want, with programs isolated from the host and from each other. Two details change how much you should trust that boundary. Protections of sandboxes against the host include the prevention of taking screenshots, and Plus replaces the token creation mechanism of the pre-open-source version, which the project says makes sandboxes more independent in the system. Browsers get their own admission of defeat. A browser compatibility wizard in the Plus edition creates templates for unsupported browsers, which is a way to generate a workaround rather than a promise that a given browser is supported.

The network side is four separate controls, not one on/off switch

Sandboxing a program is not the same as isolating its network, and Plus treats the two separately. There is a network firewall per sandbox which supports the Windows Filtering Platform, and separate DNS control by blocking or redirecting. There is also a way to force programs to automatically use a user provided SOCKS5 proxy, and a set of options for blocking access to Windows components such as the printer spooler and the clipboard. The consequence for anyone configuring this is that you can have a sandbox with disk redirection and full connectivity, or the same sandbox cut off at the firewall, and the DNS setting is independent of both. For untrusted code that resolves names on your behalf, the redirect and block options are the controls that matter, and the SOCKS5 option is the one that changes where your traffic appears to come from. Classic reaches none of these through its interface, so a Classic user who wants them is editing configuration by hand.

Triggers, snapshots, and 7z export cover what a sandbox does over time

Most sandbox documentation is about the moment a program starts. The Plus feature set also covers the states around it. There is a trigger system that performs actions when a sandbox goes through different stages, named as initialization, box start, termination, and file recovery, which means a policy can be attached to a phase rather than to every process inside the box. A Snapshot Manager takes a copy of any box so it can be restored when needed, and sandboxes can be imported and exported to and from 7z files, which is the practical way to move a configured box between machines or keep one per task. An Encrypted Sandbox provides an AES based data storage solution. Global hotkeys can suspend or terminate all boxed processes at once, and the sandbox list itself is searchable with Ctrl+F. Memory is bounded too, per process and in total, and the number of sandboxed processes per box can be capped, which is the control that keeps one runaway program from filling memory.

The custom UAC dialog and the syscall restrictions decide what a privilege prompt means

Windows asks a question when a program tries to gain administrator rights, and Sandboxie has an opinion about the answer. A custom UAC dialog lets you fake a permission, grant it, or cancel the elevation attempt, so a test can proceed past a prompt that would otherwise stop it. Privacy mode sandboxes are described as protecting user data from illegitimate access, and security enhanced sandboxes restrict the availability of syscalls and endpoints, which is a deeper cut than a file redirect. Two smaller controls are worth knowing. One feature prevents sandboxed programs from generating an unnecessary unique identifier in the normal way, which removes a fingerprint signal, and another feature can make a process itself unsandboxed while its child processes stay sandboxed, which is a deliberate hole you can open for a launcher. Privacy mode is also a Plus feature, so a Classic user cannot reach it from the interface at all.

The documentation lags the feature list, and the forum is a partial archive

For a security tool, stale documentation is a cost you should price in. A GitHub copy of the Sandboxie documentation is maintained at `sandboxie-plus.github.io/sandboxie-docs`, and the README says plainly that more volunteers are needed to keep it updated with the new changes. It also recommends checking the issue labels to track current issues, which is an admission that the docs are not the fastest source. The old Sandboxie forum, previously maintained by Invincea, survives as a partial archive, and the project gives you the search syntax to work with it:

site:https://sandboxie-website-archive.github.io/www.sandboxie.com/old-forums/

Partial archive is the important word, and the Classic edition leans on that archive for its custom script workarounds. Meanwhile the feature record lives elsewhere: the README suggests finding the sign `=` with Ctrl+F in `CHANGELOG.md` to spot more features. So a new Plus option may exist before any page describes it, and the two places to check are the changelog and the labels. When you need to know what a program did rather than what the docs say, the project points outside itself again, to an add-on called LogApiDll that adds verbose output to the Sandboxie trace log and lists invocations of relevant Windows API functions.

No install command, two version numbers in one tag, and Windows 7 as the floor

Expect no command line from this project. The download section of the README is a single link to the latest release, the stated system requirement is Windows 7 or higher on 64-bit, and that section documents no installer command. Distribution runs through GitHub Releases, and the repository carries GitHub Actions workflows for codespell and for winget. Watch the tag names. The newest three releases are named v1.19.0 with a second number 5.74.0, v1.18.8 with 5.73.8, and v1.18.7 with 5.73.7, so one release carries both a 1.x line for the fork and a 5.7x line inherited from the earlier code, which makes any dependency or script that parses a Sandboxie version ambiguous. The tree around it is Windows native: `Sandboxie/`, `SandboxiePlus/`, `SandboxieTools/`, an `Installer/` directory, the batch scripts `MergeDbg.cmd` and `TestCI.cmd`, and both `AGENTS.md` and `CLAUDE.md` at the root.

Editorial conclusion

Adopt Sandboxie Plus if you need the per-sandbox firewall, the trigger system, or the security enhanced restrictions, because those exist in the Qt interface and are awkward to reach from Classic. Do not adopt Classic expecting parity: its MFC interface is no longer developed, and the project says it is not recommended for the latest security options. Verify first which of LICENSE.Plus or LICENSE.Classic governs the edition you download, since the two live side by side in one repository under GPL-3.0, and read SECURITY.md before you point it at anything you do not control.

Frequently asked questions

Official sources

1. License: GPL-3.0
2. Project website
3. README
4. Releases
5. sandboxie-plus/Sandboxie on GitHub