A proprietary SaaS solution is one that uses a specific vendor's software and platform, which may not be compatible with other vendors' solutions or industry standards. This can result in vendor lock-in, which means that the organization becomes dependent on the vendor and cannot easily switch to another provider or solution without significant costs or risks. Vendor lock-in can also limit the organization's ability to negotiate better terms or prices with the vendor. Integration issues can arise when the proprietary SaaS solution does not support open standards, which are widely accepted and interoperable protocols or formats that enable different systems or applications to communicate and exchange data. Open standards can facilitate integration with other cloud or on-premise solutions, as well as enhance portability and scalability of the cloud services. If the SaaS solution does not adopt open standards, the organization may face challenges or limitations in integrating the solution with its existing or future IT environment, which can affect the functionality, performance, and security of the cloud services. Reference: CompTIA Cloud Essentials+ Certification Study Guide, Second Edition (Exam CLO-002), Chapter 2: Cloud Concepts, Section 2.3: Cloud Service Models, p. 62-63.