In which situation could cloud clients find it impossible to recover or access their own data if their cloud provider goes bankrupt?

In the context of cloud computing, vendor lock-out refers to a scenario where clients are unable to access their data or services because they are dependent on a specific cloud provider's infrastructure, tools, and processes, which may not be compatible with other providers or formats. If a cloud provider goes bankrupt, clients may find themselves in a difficult position where their data is effectively inaccessible. This situation arises because they might not have the ability to export their data or move it to another platform due to proprietary formats or the absence of necessary tools.

Vendor lock-in, while similar, emphasizes a lack of flexibility and difficulty in migrating to different systems but may not necessarily entail total data inaccessibility. Multitenancy refers to a shared infrastructure among multiple clients, which increases efficiency but isn't directly related to data recovery issues during bankruptcy. Lastly, a multicloud approach encompasses using multiple cloud services from different vendors to mitigate risks, thus providing redundancy that can help ensure data recovery in such situations. Therefore, vendor lock-out stands out as the situation where clients could find themselves completely unable to recover or access their data if their cloud provider goes bankrupt.