What causes documents to become corrupt?

One of the primary causes of document corruption is converting documents from one format to another and back repeatedly. This process, called round-tripping, greatly increases the document's chance of becoming corrupt. Document corruption can also be caused by the use of excessive direct formatting. Word is a styles-based word processor. Direct formatting increases the file size of documents and slows processing down. Copying text from foreign applications, such as WordPerfect or the Internet, without using Word's "Paste Special Unformatted Text" or "Keep Text Only," copies the formatting codes of the source text, a known cause of document corruption.  more