Following the change from X-band to S-band antenna operations around January 2008, the Hinode instruments have suffered from data loss problems. For EIS between February and September 2008, around 15 % of data have been lost. Since early September the situation has improved somewhat and only around 2-3 % of data are going missing.
The missing data are evidenced by one of the following:
The last two types are fairly easy for a user to spot, but if a FITS file is missing the only way you can find this out is by checking what was planned for EIS for the day you are looking at. To do this, do (in IDL):
IDL> s=fix_zdbase(/eis)
IDL> eis_mk_plan
and choose the date you're interested in.