@Tazwar_Belal1 I uploaded a version of file after going through this sequence:
sqlite3 <old-filename> .dump | sqlite3 <new-filename>
The new version opens for me (eventually!). Let me know if you get a chance to test it and compare it with the expected content. I can confirm that your file is indeed corrupt at a low-level. We’ve started some work to change the default SQLite settings used by Grist based on your feedback.