How to recover an unsaved PDF after a crash
PDF by Zaweba copies unsaved work every 60 seconds and offers to recover it when the app next starts, so a crash or power cut costs you very little.
After a crash, just start PDF by Zaweba again. Every 60 seconds the app copies any document with unsaved changes to a recovery folder, and at the next start it offers to recover those copies or discard them. Choose recover and you are back to where you were, give or take the last minute's work.
Crashes are rare, but power cuts, a laptop battery that dies in the middle of something and a Windows update that restarts the PC overnight are all familiar. Autosave is there so that none of them costs you an afternoon of edits.
How autosave works
The rule is simple. If a document has changes that haven't been saved, a copy of it goes into a recovery folder every 60 seconds. A document with no unsaved changes is left alone, since the file on disk is already up to date.
When you close the app normally, those recovery copies are removed, because there's nothing to recover. They only survive when the app didn't get the chance to close properly, which is exactly when you want them.
If a PDF is protected with a password, its recovery copy stays protected too. A crash doesn't leave an unprotected version of a private document sitting on the disk.
Step by step after a crash
Open PDF by Zaweba again. It notices the recovery copies and offers you the choice to recover or discard them.
Recover them if you want your work back. Each document opens with the changes it had at the last autosave. Look through it, check your most recent edits are there, and then save it properly over the original or as a new file. Until you save, the work only exists in the recovery copy.
Discard them if you know you don't need them, for example if the edits were only experiments. Discarding can't be taken back, so if you are unsure, recover first and decide afterwards; you can always close without saving.
Getting the most from it
The interval can be changed in the settings. Sixty seconds suits most people. If you do heavy editing where a minute's work is a lot, set it shorter. Setting it to 0 turns autosave off, which you might do on a shared machine where you would rather no copies were kept, but think twice before doing that on your own PC.
Autosave isn't a substitute for saving. It's a safety net for accidents, not a backup. Press Ctrl+S at natural pauses as you work, and keep copies of important files somewhere other than your PC.
Other ways back
Autosave is about crashes. For other kinds of loss, the app has more help. Undo goes back step by step, with each change named, such as Undo Change text. Revert to saved returns to the file as it was when you opened it or last saved it, and it is itself a step you can undo if you change your mind.
If the PDF has been saved more than once in the incremental way, File > Earlier versions opens each of those saves in its own tab, which can rescue an older state of the document that a later save went over.
And when another program changes the file you have open, the app can reload it, asking first if you have unsaved changes, so your work isn't thrown away without warning.
None of this needs an account or an internet connection; the recovery folder is on your own PC. It's one of the quieter features of PDF by Zaweba, and the kind you only notice on the day it saves you.
