Are you using ENVI 5? There were some file I/O issues in previous versions of ENVI.

Hi MariM, thank you very much for your reply. yes, I am using ENVI 5.0. the procedure I am doing is very simple.. just subseting. so from basic tools - resize data. but every time I run it, it returns that error. have you ever processed .ecw files in ENVI? if yes, did you get the same error and how did you resolve it?? thank you very much for your help. Cheers, Tania

I just ran a test opening an ECW file (80k x 60k x 3bands) and saving out a subset using the Resize Data tool and it worked without error. I did find a report that the latest ECW library includes jp2k compression and that ENVI does not support this library. It could be that your file contains jp2k compression and it is not supported.