File migration occurs when files are transferred from one hardware configuration or software application to another. It is one of the most well-known and frequently applied preservation strategies, relatively inexpensive, and simple to implement. At the same time, migration is also the most widely criticised preservation strategy.
An example of file migration is the movement of a file from Word 97 to Word 2000, or, in a more complicated example, from Apple Macintosh to Windows. There are three main arguments against migration:
- The results of the transfer are often unpredictable. This is mostly down to the absence of documentation, or because initial testing was insufficient. When a new version of software comes to the market, many people simply upgrade and update their files. This not infrequently leads to the loss of information. The new software does not always interpret the file in the same way as the previous version; as a result of this difference, content, structure, appearance, or behavioural characteristics can be lost.
- Migration can have an impact on the authenticity of a record. All records must be preserved in an authentic manner, because otherwise the meaning and the validity of the record cannot be ensured. This has both legal as well as archival implications.
- Migration may need to be repeated every few years.
In spite of these objections, migration remains a good preservation strategy for organisations that want preserve certain types of digital objects, such as databases, spreadsheets, or text documents, just for the short term (i.e. a maximum of ten years).