I have created one Extension in NAV 2018,installed properly worked but when I uninstalled this extension from Extension Management page and again installed then it show that error...
"Could not upgrade the NAV extension 'FirstExtension' due to the following error: 'The following tables contain data but cannot be upgraded because the relevant upgrade instructions are missing"
if anyone knows regrading that please suggest me.
Is it the same version you are installing?
Not seen this error with Extension v.2. Did you do this extension the old way, or the new with VSCode?
Did you write upgrade codeunit?