what action it will take with regard to landlords that did not register their tenants’ deposits with the tenancy deposit protection scheme…

The Scottish Government continues to work with the scheme providers and other stakeholders such as Citizens Advice Scotland and Shelter Scotland to encourage compliance with the law.
The Scottish Government recently introduced the Tenant Information Pack which provides key information for tenants and landlords in an easy to read format. From May 1st, landlords have a legal duty to provide the Tenant Information Pack to new tenants. The pack includes information on tenants’ rights with regards to their deposit being protected in a Tenancy Deposit Scheme.
The launch of the pack is supported by a new website: rentingscotland.org, which offers practical renting guides for tenants and landlords in Scotland’s private rented sector. Renting Scotland is jointly funded by the Scottish Government and Shelter Scotland. The website is an industry-wide information hub for both tenants and landlords in the private rented sector in Scotland.
Private landlords have a duty to protect tenants’ deposits with one of the three approved tenancy deposit schemes. If they fail to do so the tenant may apply to a sheriff to enforce the law. The court may order the imposition of a financial penalty of up to three times the deposit on a landlord. In addition, local authorities may take such a breach of housing law into account when considering the fit and proper test for landlord registration and licensing of Houses in Multiple Occupation.