As recommended by Expert in the MS Community, moving it here:
After installing and starting Metro apps, they close immediately, showing the window-box just for a fraction of second.
There are 3 different error messages in the "Applications" log:
Provider: ESENT, EventID 454
DllHost (7620,U,98) Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: Database recovery/restore failed with unexpected error -1907.
Provider: ESENT, EventID 494DllHost (7620,U,98) Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: Database recovery failed with error -1216 because it encountered references to a database, 'C:\Users\domainadm\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\AppData\Indexed DB\IndexedDB.edb', which is no longer present. The database was not brought to a Clean Shutdown state before it was removed (or possibly moved or renamed). The database engine will not permit recovery to complete for this instance until the missing database is re-instated. If the database is truly no longer available and no longer required, procedures for recovering from this error are available in the Microsoft Knowledge Base or by following the "more information" link at the bottom of this message.
Provider: ESENT, EventID 490 DllHost (7620,R,98) Microsoft.Windows.Cortana_cw5n1h2txyewy_NOEDP_LEGACY_IDB: An attempt to open the file "C:\Users\domainadm\AppData\Local\Packages\Microsoft.Windows.Cortana_cw5n1h2txyewy\AppData\Indexed DB\IndexedDB.edb" for read / write access failed with system error 5 (0x00000005): "Access is denied. ". The open file operation will fail with error -1032 (0xfffffbf8).
Please note that my account has a system admin level, but it is not "domainadm", which you can find in the path. I have no Idea why is it accessing "Users\domainadm\" Seems like they made some mistake when blocking Cortana on "for Workstations" versions of Windows where you do not have to do anything about pre-disabled Cortana.
So I need to fix it somehow for allowing modern apps operation.
I got this laptop in the company from our IT dept. There were many Windows10 computers, but only this has the problem. They made something wrong when preparing it for the workplace. Since it takes months and burning-hot disputes when applying for reinstallation in a corp, and I already had to do it 3 times, the only option left is pinpointing the problem on the workplace without their "help".