Certain EMM files cannot be opened

If you try to open a file bearing the EMM extension and known to contain a map, and MYmap always reports that the file is invalid, please check whether the author of the map has used MYmap or MindJet MindManager Smart (respectively MindJet eMindMaps). MYmap stores documents using the extension EMM. The product MindManager Smart (respectively eMindMaps) from MindJet also saves its document using the extension EMM. The EMM format used by MindManager Smart (respectively eMindMaps) is different from the EMM format for eminec MYmap. It is not possible to import an EMM from MindManager Smart (respectively eMindMaps) to EMM for eminec MYmap or vice versa.