Hi,
Even that you have enough RAM memory each software (and MOHID GIS included) can only use not more than 1GB of RAM (in 32bit systems). So if you have opened several files and try to open one big HDF it is probable that the memory used by MOHID GIS go higher than 1GB and it can not open the file.
And the size that MOHID GIS uses in memory for a 400MB file can be higher than that.
What is the size of the HDF?
Try to open the HDF with MOHID GIS without any layer loaded.
Other option is to try to reduce the HDF size with the tool ConvertToHDF5. The tool can be downloaded in
http://www.mohid.com in download area and instructions here:
http://wiki.mohid.com/wiki/index.php?title=ConvertToHDF5Other option is to use the new interface for the model, MOHID Studio. The tool can be downloaded here
http://www.actionmodulers.pt/default.aspx?canal=64. It is licensed as you can see in the link but free licences can be asked if you are doing research.
Best regards,
David