If your OST file has become inaccessible and Outlook won't open it, converting it to HTML is a good way to view your emails directly in a browser. You can try DataVare OST to HTML Converter Expert for this. It can open an OST file even if it's orphaned or corrupted and convert all the emails into simple HTML pages that work in Chrome, Edge, or any other browser. The tool preserves your formatting, attachments, and folder structure, so everything remains familiar when you open it. Once converted, you can browse your emails easily without needing Outlook at all. I used it once when an OST file wouldn't load, and it made accessing my data much easier.

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.