Post mortem
Universal Apps run shared host systems. These host systems have - of course - limited file storage. Initially we enforced hard file system quotas, but an underlying bug in BTRFS caused issues with that. So we lifted the hard limits and allowed exceeding the including file system limits. For Universal Apps, there is no automatic scaling, so that solution is actually better for clients too. We overbook storage, roughly by the factor of three, which would allow clients to use as twi...