Accu-Chek COMPACT PLUS Owner's Booklet page 79

The test drum 90-day use-by period
has expired. If the correct time and
date were set on the meter and the
drum door has not been opened
since the installation of the test
drum, discard the old test drum and
insert a new test drum.
Chapter 5: Maintenance and Troubleshooting 77
ACCU-CHEK Customer Care Service Center 1-800-858-8072
The drum door was opened and
closed with a partly used test
drum inside, or a partly used test
drum was inserted.
If there was a partly used test
drum in the meter and it took
longer than two minutes to
replace the batteries, the year,
date, and time have to be reset.
When the year, date, and time
are reset, the meter does not
know how long the partly used
test drum has been in the meter.
You should run a control test
to verify that the test drum is
useable. See Chapter 2, "Why
Run Control Tests?"