Recovering Data From Corrupted Files

Article
02/20/2014

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By Scott Kirwin

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Published in TechRepublic's Windows Support Professional (TechRepublic.com)

It was the perfect PowerPoint presentation. It would allow her to finally stop dreaming about that cute VW Beetle she'd her eye on for months, walk into the car dealer, and drive away in German proletarian comfort. At 54 MB, the presentation contained more than 200 slides of charts, graphs, scanned photographs, and drawings. It took several minutes to load on her Pentium 166, but when it opened it looked elegant and professional.

But, now the presentation wouldn't open. This is not a PowerPoint presentation, the message window said. She tried again. Of course this isn't a PowerPoint presentation, she thought—this is my job, my career, and my future, all bundled up in 54 MB of computer code. She tried again, and with every frantic second it became clearer that not only would her Beetle have to wait, much more hung in the balance. She had no time to re-create the presentation… there were no hard copies she could rescan into the wee hours of the morning… and of course, she didn't have a backup.

This woman called me a while back, and we tried everything to open her file. However, it had been damaged in a crash while PowerPoint was in the process of saving the presentation. Nothing could be done. The call ended with the woman sobbing into the telephone as I sat powerless a thousand miles away.

I never forgot her predicament. Since that time, recovering data from corrupted files has become something of a mission for me. In this article, I'll offer some of the tricks and techniques I've used to pry open damaged Excel, Word, and PowerPoint files. You can apply these techniques to help save the productivity lost when files go bad.

Causes of corruption

According to Emil Sildos of Concept Data (designers of Excel Recovery, discussed later in the article), the most common causes of corruption are bad sectors on storage media, lost clusters, crosslinked files, malfunctioning antivirus software, viruses, and system crashes. Although 99 percent of a file may be intact, a few missing or corrupted structures are enough to stop an application cold—leaving the user frantic and the IT professional in a jam.

General techniques

The following techniques may seem like just common sense in the tech-support field. However, it's amazing how quickly you can forget common sense in the heat of the moment.

Reboot the machine and try to open the file again. Simple, I know, but how often have you seen a reboot clear up a problem?
Run Scandisk.
Open the file on a different machine.
Copy the file locally if you're on a network; do the reverse if the file is local. In my experience, some files that for one reason or another failed to open on network drives opened fine after I copied them locally.
Reboot in safe mode or turn off antivirus software as well as any non-system applications running in the background. I've found that this technique works more often on the Macintosh platform (through disabling extensions), but it's still worth trying in Windows.

Microsoft PowerPoint presentations

We'll start with the hopeless first. In my experience, once a PowerPoint presentation refuses to open, as shown in Figure A, it isn't going to open. Nevertheless, try using the following techniques, which Microsoft recommends. Maybe you'll be luckier than me at opening such files:

Figure A: This corrupted PowerPoint 97 file won't open.

Be sure you're using the correct version to open the file. As more clients have migrated to Office 97, this is less of a problem. However, I've often had users in PowerPoint 7 try to open PowerPoint 97 attachments, resulting in the "This is not a PowerPoint presentation" error message.
Drag the presentation onto the PowerPoint program file.
Try inserting the slides into a blank presentation.
Try opening the file in PowerPoint Viewer.
If you can, try opening the file on a Macintosh with Office 98 installed. More on this suite later.

Microsoft Word documents

Now, here are some techniques you can try when a Word file becomes corrupted:

Open the file in Draft mode.
If you're using Word 6.0 or 7.0, try the following macro to turn off screen updating (the macro comes from Microsoft Technet 187309):

Sub Main Screen updating 0 Fileopen. Name = "<path of corrupt doc>\ corruptfile'sname.doc" ToolsOptionsView.Draftfont = 1 Screenupdating End Sub

Insert the file into a new document.
Link to the damaged document.
Open the file in Microsoft Wordpad or Write.
Open the file in WordPerfect.
Strip out the header information (per Technet 187309). To do so, go to a DOS prompt and type copy con+corruptdocfilename.doc newname.doc. The word CON should appear with a blinking cursor next to it. Press the spacebar 12 times and press [Enter]. Then, open the newname.doc in Word.
Open the document in Microsoft Word 98 for the Macintosh.

Microsoft Excel spreadsheets

When you try to open a corrupted Excel spreadsheet, you'll see a message similar to the one in Figure B. Microsoft recommends linking a good spreadsheet to the damaged one. Personally, I've never seen this technique work, so I don't recommend it. But, here's how to do it, for those times when you're in a jam and the client looks at you with those puppy dog eyes…

Figure B: You'll see this message when you try to open a corrupted Excel 97 file.

Open a non-corrupted workbook and a new workbook.
From the new workbook's Insert menu, choose Hyperlink and create a link to the non-corrupted workbook. Close the non-corrupted file.
The link in cell A1 displays the path to the non-corrupted file. Edit the formula in cell A1 by substituting the corrupted filename for the existing one.
If the technique fails, you'll see the error message shown in Figure C. If it works, the corrupted file will open. In this case, copy the formula down and across until the link returns blank cells.
Select the data, copy it, and choose Paste Special from the Edit menu. In the resulting Paste Special dialog box, click Values and click OK to paste the data over itself. Doing so removes the link formula, but the values returned by the link remain.

Figure C: You may experience an Excel 97 linking failure.

Figure C: You may experience an Excel 97 linking failure.

Successful strategies for opening corrupted Excel files

Using the word "successful" in an article about file corruption seems almost disingenuous. However, by using the following techniques, I've been able to open the majority of damaged Excel files that have come my way.

Open the file in Word 97, as shown in Figure D. Then, select the resulting table. (Check the document to be sure you've selected the whole table.) Copy and paste the table as text into a new Excel workbook. You'll lose formulas and formatting, but the data will be there.

Figure D: A corrupted Excel file looks like this when it's opened In Word 97 (note the corruption, represented by the paragraph mark breaking the table).

Obtain Excel Recovery from Concept Data
(https://www.officerecovery.com/excel/index.htm). You can get a free, fully functioning demo from the company's Web site. I've used the full version of the program and found it easy to use as well as effective at opening all but the most mangled Excel files.

I rely on the Excel Recovery program and recommend it as a "must have" for all technicians, analysts, and programmers who come into contact with corrupted files on a regular basis. At $148.95, the full version of the utility pays for itself after recovering only a handful of vital files. Concept Data is currently working on a version for Excel 2000 that will include formula-recovery capability. And, the company's research into a recovery utility for Word is ongoing.

Office 98 suite for the Macintosh

I'm not in the least a wild-eyed Macintosh fanatic. But when it comes to opening corrupted files of all formats, I've yet to see a more useful tool than Word 98 on the Macintosh. (Although I haven't tried it yet, I think you could place a can of tuna in front of the program and it would open.)

For example, I've used Word 98 on a Mac to open corrupted Excel files that resisted all other techniques. Here's how: Choose Open from the File menu and select the desired worksheet name. (I haven't had success selecting the Entire Workbook option.) Doing so opens the corrupted file as a table in Word. Save it as a Word 98 document—you may not be lucky enough to open the damaged file again. Select the table, copy it, and paste it into a new Excel spreadsheet. All formulas and formatting will be lost, but people are usually happy just to get the data back.

Conclusion

As long as users create files without backups, you'll be getting occasional desperate cries for help when those files become corrupted. In this article, we've looked at various techniques you can use to help recover data from corruptedPowerPoint, Word, and Excel documents.

Scott Kirwin is a systems analyst at Black Oak Computer Services in Newark Delaware. When not being "Daddy man" to his two year old son and Bob Villa impersonator to his wife, he specializes in cross platform issues. You can contact him at skirwin@black-oak.com.

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