This pattern of Error 1204 every 10–15 minutes is almost certainly caused by ongoing memory pressure combined with a recurring background process that is exhausting lock memory, not normal user activity or corruption. The RESOURCE_MEMPHYSICAL_LOW warnings confirm that SQL Server does not have enough memory to allocate lock structures, and the regular interval indicates something scheduled (such as a system task, monitoring tool, antivirus scan, or similar) is triggering it repeatedly even when no users are connected. The multiple connections from MS Access are normal and may contribute slightly, but they are not the root cause. The practical solution is to first address memory pressure (increase RAM or rebalance max server memory), then capture active sessions during the spike (using sp_whoisactive or sys.dm_tran_locks) to identify the recurring process, and finally adjust or eliminate that process; without resolving the memory issue, the errors will continue regardless of workload.