Nadya,
The low level file function idea does work well. Using fopen() returns -1 if you try opening an excel file for read\write access that is aleady opened by someone else. A potential problem I see is this: If fopen() returns a non -1 number logic tells you that the file is free to be modified. But what if from the time fclose() is issued to the time it takes Foxpro to open the excel object through ole someone else on the network opens that same excel file? This probably is a rare occasion, so maybe it will not matter.