Can you still use Windows XP offline?

Yes — you can still use Windows XP offline. Keeping an XP machine completely disconnected from the internet is the safest way to use it today, because Microsoft ended support in April 2014 and it no longer receives security updates.

What to expect:

• Hardware compatibility: XP often works best on older or legacy-compatible hardware. Many modern components may not have XP drivers, and some newer systems may be difficult or impossible to install XP on directly.
• Virtual machines: If you want to run XP on a modern PC, using a virtual machine such as VirtualBox or VMware Workstation Player is often the easiest option.
• Activation: Windows XP normally requires activation. Official online activation is no longer something you should count on, so if you reinstall it, you may need an alternate activation method if your edition and setup allow it.
• Software: Modern programs generally do not support XP, but it can still be useful for legacy industrial software, old peripherals, or retro gaming.
• Transferring files: If you move files via USB, scan them on a modern machine first and be careful about malware.

So the short answer is: yes, you can still use Windows XP offline, but only for limited legacy use, and it should stay isolated from the internet.