Mac Guest User: Know What Disappears at Logout
Guest User is designed for occasional access, not long-term storage. Before letting a visitor use it for an important task, check whether the guest environment supports that task and how any result will be retained.
Understand the temporary workspace
Apple's macOS Tahoe 26 guide states that files created by a guest are kept in a temporary folder and deleted when the guest logs out. That makes “I saved it on the Desktop” an unsafe handover statement unless the visitor has also preserved the result elsewhere.
With FileVault turned on, Apple's documented guest behaviour is more restricted: guests can use Safari but cannot access the encrypted disk or create files. Do not disable FileVault simply to turn a brief visit into a full working session.
For someone who regularly uses the computer, create a separate standard account instead. A continuing project, a large local download or a task that depends on installed application settings usually deserves a persistent workspace.
Test the visit from start to finish
An administrator can review Guest User in System Settings, Users & Groups. Guest login and guest access to shared folders are separate choices; enabling one should not become an excuse to open unrelated network sharing.
Try the intended activity with harmless material before handing over a real document. For a website-based task, confirm that the visitor can sign in, complete the activity and sign out without exposing your personal browser session.
Before logout, ask the visitor to verify any output in its intended destination. An upload progress bar is not the same as an accessible saved document. If external storage is used, confirm the file opens and eject the disk properly.
End the session explicitly. The value of Guest User comes from knowing its boundaries, including the fact that temporary local work should not be expected to survive.
Source: Apple's Guest User settings for macOS Tahoe.
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