Recently I ran into a troubling issue with ArcGIS (10.2.2) shapefiles. I transferred a shapefile with approximately 10,000 records from my local drive up onto a shared network drive at my office, using the basic function in ArcMap where you right-click the layer in the table of contents, select "Data," and then select "Export Data."

I then discovered that the copy of the file on the network drive had its attribute table significantly altered. Specifically, while the table had the same number of records as before and the file could be used normally, one particular record from the pre-corrupted version had somehow propagated itself throughout much of the rest of the table, overwriting nearly 25% of it. Thus, a previously diverse subset of records had all been overwritten with identical values from another record.

This is fairly disconcerting, because I have always been under the impression that "corrupted" shapefiles simply will not open or will raise the classic "Number of shapes does not match number of table records" error.

Has anyone encountered a similar problem before and can confirm that something like this can be caused by upload/download of shapefiles between local and network drives? Are there other potential causes for an attribute table being altered in this unique way? What are some precautions against something like this?

Standard ArcGIS tools like Feature Compare & Table Compare successfully detect the issue, but it would be nice to have enough confidence in file transfer processes to avoid having to incorporate such relatively paranoid checks into my workflow.

  • Please edit the question to give a clearer meaning to "had its attribute table significantly altered." What was it before? What was it after? Did you exclude columns in the layer definition? In general, the only way to corrupt files is to use an reliable procedure. If the mechanism copying files utilizes FTP without specifying binary transfer mode most files could be corrupted , but I don't think anyone here could do anything about that.
    – Vince
    Oct 23, 2015 at 16:12
  • Edited to clarify that the stated changes in the attribute table (a subset of previously diverse records all were overwritten with identical values) was the only way in which the attribute table changed. Everything else (fields, number of records, etc.) remained the same.
    – user14175
    Oct 23, 2015 at 17:01
  • Do you have a large SMB filer? That sounds more like a driver/controller buffer overflow issue than something ArcGIS is capable of producing.
    – Vince
    Oct 23, 2015 at 18:57


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