Please ensure that the conversion you submit is between supported file formats, as listed below. Unsupported file formats tie up our server and bandwidth the same as successful jobs. Although you’re welcome to try any conversion to see if it works, there is no refund due for conversions which are unsuccessful because the file format is not supported. When converting graphics, the source file format may simply be specified as ‘Graphic’. If you do not select any destination format, files are converted to the Microsoft Office preferred format (PNG). If you have files that cannot be converted any other way (e.g., unknown/unsupported file types, or corrupted files), the conversion service can extract whatever text is possible from them, and salvage it into text files. This works for any kind of file, not just the file types listed above. To use this option, select ‘Unknown for Text Recovery’ as the source file type. The destination format option is not available in this case, since the output is always a text file. Please note that under this option, the conversion service looks for anything in the source file that looks like text, extracts it, and puts it into the output file. So all text content will be extracted from the source file (unless it is stored in an encrypted or non-ASCII form). However, there may also be a fair amount of ‘garbage’ and irrelevant text interspersed with the actual text content. In some cases, text that was ‘deleted’ may resurface. Further, the extracted text may not necessarily be in the correct sequence. So you may have to substantially edit and touch up the converted file. However, this is still a useful last-resort option. Source.