How to Open a Private Window in Firefox (Ctrl+Shift+P)

Ctrl+Shift+P opens a new Private Browsing window in Firefox — Cmd+Shift+P on macOS. It has its own cookie jar, its own cache and its own session storage, and it discards all of them when the last private window closes. **The binding differs from Chrome's, and this is a genuine daily irritation for anyone who uses both.** Chrome opens an incognito window with Ctrl+Shift+N. Firefox uses Ctrl+Shift+P. Worse, each combination does something in the other browser: Ctrl+Shift+N in Firefox reopens a closed window, and Ctrl+Shift+P in Chrome does nothing useful. So the muscle memory does not merely fail, it produces an unrelated result — which is why people who switch browsers regularly end up checking the window title before trusting what opened. **What private browsing actually does is narrower than most people assume.** It isolates browsing state on your own machine: history, cookies, cache and site data are not written to your normal profile and are discarded when the session ends. It does not hide your traffic from your employer, your internet provider, or the sites you visit. Your IP address is unchanged and a site can still identify a returning visitor by other means. It is a local-privacy feature, not an anonymity one. **The genuinely useful applications follow from the isolation, not the privacy.** A private window is a clean second session, which makes it the fastest way to log into a second account on a service that allows only one at a time, to check how a page looks to a logged-out visitor, or to test whether a bug is caused by a stale cookie or a cached asset. For anyone building or debugging websites, that is a far more frequent use than anything to do with privacy. **Firefox enables Enhanced Tracking Protection more aggressively in private windows**, blocking trackers that are permitted in normal browsing. This has a practical consequence when testing: a site that behaves differently in a private window may be reacting to blocked third-party requests rather than to the absent cookies. When a page misbehaves only in private browsing, that is worth ruling out before assuming a session problem. **Containers are the Firefox-specific alternative and often the better tool.** A container tab isolates cookies and storage under a named label — Work, Personal, Testing — and unlike private browsing, containers persist. You stay logged into three separate accounts indefinitely, in ordinary tabs, without a window per account. For anyone using a private window purely to hold a second login, containers do the job properly. **Extensions are disabled in private windows by default.** Each can be individually permitted from the add-ons manager. That default is a sensible security posture and it does mean a private window is not a like-for-like copy of your normal browsing environment — worth remembering when something works in one and not the other. **Downloads survive the session.** Files saved from a private window remain on disk after it closes — private browsing discards browsing state, not files you deliberately downloaded. The download itself does not appear in the normal downloads list, which occasionally leads people to conclude it failed when the file is sitting in the destination folder as expected.