If you are facing an inaccessible OST file and want to convert it into HTML format. It is the best option to recover the data from an inaccessible OST file. I also chose it, a few weeks ago, and I also faced a similar issue. I use WholeClear OST to HTML Converter to convert my OST file into HTML format. It can easily convert single or multiple OST files at once without a limit on file size. It allows for converting selective data instead of wasting time to convert the entire OST file. It offers a user-friendly interface, which makes it easy to use. I recommend using this software for converting your file.