Hello Experts,   I am trying to run the mri_convert command prior to the recon-all command on Siemens T1 dicoms (as suggested in the archives). I am using freesurfer version: freesurfer-Darwin-lion-stable-pub-v5.3.0, Mac OS X Lion 10.7.5 I am using the command below: mri_convert -it siemens_dicom -ot mgz 1002/IM-0001-0001.dcm 2001.mgz   Below is the command line error I receive, it is a similar error I receive when I try to use the command recon-all on the Siemens dicoms. I have used freesurfer before on GE dicoms and never had a problem running recon-all. Is this error message particular to the Siemens dicoms, and would you be able to tell me how to proceed? Thank you very much for you help, Cat   reading from 1002/IM-0001-0001.dcm... Getting Series No Scanning Directory INFO: Found 130 files in 1002 INFO: Scanning for Series Number 2 INFO: found 128 files in series INFO: loading series header info.   INFO: sorting. RunNo = 1 WARNING: Run 1 appears to be truncated   Files Found: 128, Files Expected (lRep+1): 1 FileName                    1002/IM-0001-0001.dcm Identification             NumarisVer        syngo MR D11             ScannerModel      Skyra             PatientName       RS-FMRI^RS-FMRI Date and time             StudyDate         20130222             StudyTime         082109.140000             SeriesTime        082812.906000             AcqTime           082237.315000 Acquisition parameters             PulseSeq          *tfl3d1_16ns             Protocol          SAG MP Rage             PhEncDir          ROW             EchoNo            1             FlipAngle         8             EchoTime          3.03             InversionTime     1000             RepetitionTime    2400             PhEncFOV          0             ReadoutFOV        0 Image information             RunNo             1             SeriesNo          2             ImageNo           1             NImageRows        256             NImageCols        256             NFrames           128             SliceArraylSize   0             IsMosaic          1             ImgPos            -78.6002 128.0000  93.1332             VolRes              1.0000   1.0000   1.2500             VolDim              0        0        0             Vc                 -0.0000  -1.0000   0.0000             Vr                 -0.0000  -0.0000  -1.0000             Vs                  0.0000   0.0000   0.0000             VolCenter           0.0000   0.0000   0.0000             TransferSyntaxUID 1.2.840.10008.1.2.1   WARNING: file 1002/IM-0001-0001.dcm does not contain a Siemens ASCII header has this file been anonymized? ERROR: cannot unpack mosiacs without ASCII header