Posted: Fri 18 Jan 2013, 04:13 Post subject:
Corrupt Spreadsheet Subject description: How can I repair or extract data from a corrupt spreadsheet?
I have a Spreadsheet file originally created with Gnumeric (in Puppy Linux) but subsequently saved as as an .xls file. It has opened and functioned perfectly well for several weeks but has now just suddenly decided not to open in either Gnumeric (in Puppy) or with LibreOffice(in CorePlus) ie. nothing happens when I (double)click on the file in the File Manager and it won't open from the terminal or from within any relevant spreadsheet program either. The 'Properties' indicate that the 'contents include: CDF V2 Document, corrupt: Can't read SAT'; (using 'file' in the terminal produces the same message).
I have tried copying the file elsewhere and also tried to change the permissions (by right-clicking the file and via the terminal) but only manage to get a message back saying 'Read-only file system'.
I have also attempted to repair the file and/or extract the data in Microsoft Excel (on a borrowed computer) but that has also failed. I have also not been able to rename it (eg. as a .xml file to try to get it to open in a browser). I was connected to the internet with this file open immediately before I last used and saved it - it may be that someone has well and truly 'done a number' on it - it was the single most important file I had. Quite a coincidence. (Incidentally I have tried to see what Testdisk could do to help but (as usual) had no luck in getting Testdisk to do anything with it. Also, the problem file is on an USB but the rest of the files on the USB seem to be OK. The problem file won't even copy or move to my hard drive or anywhere else).
I wonder whether anyone can please throw any light on how I may now be able to repair the file and/or salvage the data (using Linux).
Joined: 24 Jul 2005 Posts: 1298 Location: UK
Posted: Fri 18 Jan 2013, 08:59 Post subject:
Files can get corrupt for any number of reasons. That is why if you have really important data you should have a backup strategy! You will in future. I would suggest backing up whatever else is on that USB in case the media is starting to fail.
If you cannot copy or move the file it sounds like it cannot be read and is really corrupt. Do not do anything that will write anything to the USB device until you have recovered your data. If it were me I would try one of two approaches:
(a) use a binary viewer (?) or text file viewer (geany?) to see if I can see any info worth preserving. It will probably be all gobble-de-gook though.
(b) use a file undelete tool to see if some previous versions that have been saved are still available on the drive which can be recovered and viewed. If so you may be able to get the bulk of your data back and you can proceed to work out what was added/amended since it was saved. Unfortunately, I don't know what tool exists for Puppy. Sticking Linux File recovery into Google shows many options. I have seen Photorec mentioned amongst the Google references and in magazines but don't know if it works with Puppy.
My current favourite using Windows is Recuva.
If you see a file to recover then recover it to somewhere else, not the USB device. Only when you are satisfied you have got your data back, or as much as you are going to get, should you consider using the USB device again.
Posted: Sat 19 Jan 2013, 05:31 Post subject:
Thanks for your consideration of the problem. I have just managed to recover a very recent copy of the spreadsheet using Photorec and that will be sufficient. I will bear in mind your advice for the future. Problem solved.
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