Arcean, many thanks for your time. I have been doing more testings and Gnumeric does update the file date when the spreadsheet is modified. But the native file manager of Maemo 5 does not upgrade the file date until it is opened again. This was what induced me to think that it was the cause of my synchronization problem. The latter persists. When I run DropN900 to synchronize with DropBox, sometimes spreadsheets edited with Gnumeric are not synchronized, as if the file had not changed. This does not happen with text files, for example. But right now I do not know if the problem is in Gnumeric, in DropN900, or whatever. I will try to get more details, but for the moment I cannot trust the synchronizations. Thanks again for your quick response.