I installed the zcash client (not sure which version) on ubuntu 16.04 lts along with the ZCash Swing Wallet UI 0.65 when the blockchain was launched and had mining rewards sent to a shielded address.
The laptop is equipped with a Pentium 2020M with 8GB of RAM (it shows as 7.8GB).
I can still receive rewards to the z address and can send and receive from the wallet t addresses.
However, any attempt to send the full or partial z balance to either a t or z address results in one of the two following error message.
From z to t, I get: Error Message is: Could not find previous joinSplit anchor.
From z to z, I get: Error message is: 18: bad-txns-joinsplit-requirement-not-met
Please help me transfer my z balance to a t balance.