Lightroom :: Photo Import Doesn't Work

I am using lightroom 4 and 5 on a Mac. Although preview of photos to be imported is shown I only get the message that the import could not be carried out (1) and the option to save the data as a :txt file. This was with Lightroom 4. It started first with being unabel to import directly from the camera, then I swithched to inserting the SD card directly into the laptop. This worked only after first downloading to the desktop. Later this didn't work either. I thought the program had become defect. Preview still worked and export is fine. I therefore updated to Lightroom 5 in the hope that this would solve the problem. However everything remains the same. Import still doesn't work with photos of any format. e.g. jpg or RAW.