You may use search engine on phrase like ms outlook pst repair tool download or something, I found some helpful articles, guides, resources on this query and [https://www.openfiletool.com/pstopen.html|MS Outlook Software] from Microsoft
If such an error takes place while opening PST files, this might be a corruption case. I'm little sure about the corruption here as the user followed the things asked in the error with no luck. SCANPST.EXE, the Inbox Repair tool for MS Outlook, can play an important role in this situation. It can fix the PST files if they are corrupted. Sometimes it may fail if the files are severely corrupted. In such situation, some third-party PST repair tools can be useful.