Storage Gateway Appliance Freezes

After 18 months of flawless performance my gateway on premise appliance now freezes every week or so. I increased the number of shared buckets from 3 to 7 but understand that the limit is 10. The start support session button on the devices interface fails to initiate a support session. The SMB shares and the device interface ceases to function (or is unresponsive) when the unit freezes. Has to be rebooted at front panel - it seems fine for a week or so then freezes again. Any suggestions for troubleshooting or support?