Hardware faults

Error message "no data carrier found" or "no system found".
Server or PC does not start.
Hard disk makes clicking or scratching noises.
Hard disk does not spin any more.
Hard disk "tingles".
Hard disk overheated.
Damage from fire or water (sweet water, salt water, rain water, etc).

Voltage surge occurred, electronic parts do smell burnt or chips turned black.
Data medium was already opened by non-specialist.
Tape damaged.
Optical medium (eg CD, DVD, BlueRay-Disc) is faulty.
A flash medium (eg USB Flash Drive, CompactFlash, SmartMedia) is faulty.

Software defects

Data medium was formatted and/or partitioned.
Data or directories were deleted.
Data are shown to have a size of only 0 bytes.
System was newly installed or data and/or directories were partly overwritten.
Directories or data suddenly vanished or cannot be found anymore.
Data or directories were copied in a wrong direction (eg backup to data).

Errors in the data system, the operating system wants to conduct a system check.
Password was forgotten (eg hard disk (HDD)-password, bios- or data-password).
Computer viruses.
A data medium (eg hard disk, flash) is suddenly empty, the operating system wants to format.

Raid

Raid-Array is indicated as being "critical" or "offline".
Disks vanished from Raid-Array.
Rebuild of Raid-Array terminated.
Raid-Array was reinitialised one more time or rebuilt faultily.
Defects in the hard disk, caused by or occurring during a rebuild.
Defect Controller.
Bad support from the side of the supplier, eg if he, just for lack of other options, advices to rebuild Raid5 or even to delete it and put it together again.
Bad user guide in case of defects.
Mistakes by the user (disks are being changed hazardly, more than one disk being replaced at the same time, all options in the Controller-Bios are being tried out at the same time).

Data faults

A fault in the data base (eg MS SQL Server (.mdf, .ldf), Oracle (.dbf), MySQL (.myd), Access (.mdb), FileMaker, Intebase, Firebird, Paradox, PostgreSQL, Sybase, SQL Anywhere, Visual FoxPro) has occurred.
Mail data base (eg Outlook (.pst), Outlook Express (.dbx), Windows Mail, Thunderbird, Eudora, Exchange Server (.ost, .edb), Lotus Notes) is faulty.
A document is not represented correctly anymore (eg Excel (.xls, .xlsx), Word (.doc, .docx, .rtf), Powerpoint (.ppt, .pptx), Autocad (.dwg), Money, OneNote, Project, Publisher (.pub), Works, JPG, PDF, TIFF, WordPerfect, OpenOffice).
An archive (eg ZIP, Tar, GZip (.gz und .tar.gz), RAR, BZ2, 7Zip, NTBackup bzw. Windows Backup (.bkf), Veritas Backup, Seagate Backup) is faulty.

Related topics, read more:

• Loss of data
• Procedure & Costs
• Data media & Systems