After i uninstall my minecraft and install it again all of my world is lost

Thank you for your report!
However, this issue is Incomplete.

Your report does not contain enough information. As such, we're unable to understand or reproduce the problem.

Please review the guidelines linked below before (specifically, take a read through the Writing Helpful Bug Reports for Minecraft) before making further reports.

As this sounds more like a technical support issue, our amazing community is likely more suited to help you and can be found using the quick links below.

Also please note, this section of the JIRA is for the Dedicated Server software, as your bug report is in reference to the "Minecraft (Bedrock codebase)" game, please head here when reporting in the future.

Good luck and Happy Minecrafting!

Ionic

Quick Links:
📓 Issue Guidelines – 💬 Community Support – 📧 Customer Support – 📖 BDS Wiki – 📖 FAQs