nccreate: error with "unlimited" dimension

Please

I'm trying to export a 3D (time x latitude x longitude) matrix into a netcdf file by using nccreate. The time dimension has to be "UNLIMITED" because of climate model input format. After using "inf" for the time dimension as

nccreate([Path filename '.nc'],filename,'Dimensions',{'time',inf,'lat',size(Data,2),'lon',size(Data3)},'Format','classic');

I got the following error

Error using netcdflib
The NetCDF library encountered an error during execution of 'open' function - 'Unknown file format
(NC_ENOTNC)'.

I'm using a R2014a version

thank you in advance

Carlo

[Ashish Uthama]

Carlo, a full runnable reproduction step would help.