Maps Not Found

i have an SD card with 238 G free and 34 G free on internal
Galaxy Tab S6 Lite
Android 11

renamed the folder as above with same result; zip cant be opened

i again deleted from the appstore and re installed. I was again asked to allow qtvlm access to the qtvlm folder which was (this time) correctly displayed. I confirmed permission there was further dialogue about searching for and updating files (not seen previously) then maps downloaded. Still cannot open zip file

I had charts in seprate location. Today I have tried add it to Documents/qtvlm.

I have tried to reinstal by deleting Documents/qtvlm and by renaming but i did not work. I have tried to do that both ways many times

By the way I remebered that I had qtVlm also on my phone and whe I checked it worked! I uninstaled it, deleted Documents/qtvlm, instaled recent version and now it has the same issue...
Phone Galaxy S 10
Android 11

Update.

I have instaled successfully in tablet (except for message "Reading polars. imposible to open file boat class_40.csv"). This time I have uninstaled app, deleted all files from Documents directory (not only qtVlm folder) by using PC (previously I used Cx File Explorer).

I have tried to do the same on phone, but for the phone it did not work.

 

That is useful information thanks. Still searching on that one but difficult since here on 2 different devices all is working as expected.