Richard22 wrote:a) Why is this happening?
Your file has been corrupted. OpenOffice cannot understand the content and as a last chance offers the ASCII Filter Options dialog in case it happens to be a valid file which has been saved in an unusual format by another program like an old version of Microsnot Word. But that is almost never the case. If you have a backup of the file, copy the backup to the corrupted file. Do not edit the backup directly because it is your recovery from future problems.
Richard22 wrote:b) Is it something in the way I save it?
Many, many people have had their files corrupted because they do not give the save process enough time to complete before turning off the computer or putting it to sleep. A power failure can also cause this, either loss of mains or battery running out of charge. Since you use OpenOffice, always save Writer files in ODT format. Saving in another format, like DOC, risks loss of data or features.
Richard22 wrote:c) Is there a way to prevent it?
Give the save process plenty of time to finish before turning off the computer, perhaps a minute or so depending on your system configuration. If your computer runs from a battery, immedately heed any low battery warning, and save without delay using File → Save to a "Emergency My document.odt" file, then save a second time to your original document location. If your computer runs from mains power purchase an
uninterruptible power supply which will give you a few minutes to save any work when mains power fails. Do not leave a document open when you are not using the computer. Learn how to instruct your operating system to make regular backups for you. Consult the documentation for it or use a web search for instructions.
Search the forum for
"ASCII Filter Options" to read more about what others have learned about this difficulty.
If this solved your problem please go to your first post use the Edit button and add [Solved] to the start of the subject field. Select the green checkmark icon at the same time.