ArcMap and ArcCatalog both show the a "?" next to several shapefiles in the catalog window. Additionally, a two-letter prefix "ml" has been added to the file name, but only when viewed in Catalog, not in Windows File Explorer. I am unable to open, load or even view properties of these files. Coworkers do not have this problem with the same files (in a networked shared folder). There are other files in the same folder that do not have this issue. This question is related, but the problem there was a missing .dbf file. All files that I have showing this error contain files with extensions: .cpg, .dbf, .prj, .sbn, .sbx, .shp, .shp.xml, .shx, so this didn't solve my issue.

Question mark and "ml" prefix errors

What I have tried:

  • Adding file to ArcMap .mxd. Got error "Error: failed to open the dataset"
  • Opening file in ArcCatalog. Got error "Error: failed to open the dataset"
  • I was able to successfully open and view the same file from within Python/Geopandas with no problems, so I assume this is an ArcGIS-specific issue.
  • I can open and use any of these shapefiles in QGIS without any issues.

I'm running ArcGIS version 10.5.1 on Windows 10.

What am I missing?

EDIT based on comments: The folder where these files are located, "County Layers (check against Shared Data)", is not a .gdb folder, nor is it in one. There are other .shp files in this same folder without this issue.

Here's all the component files of ParcelAddressOwner.shp as shown in File Explorer: Shapefile in File Explorer

Based on Michael Stimson's comment, I used Geopandas to write out a new .shp file. I wrote the file, titled "Zone A Project Creeks - wtrcrs_line_Test.shp", to 3 different folders: 1) the original folder "County Layers" 2) one level up in "Data" and 3) two levels up in "GIS". Note that the file saved to folders "Data" and "GIS" in the image below do not have the ? or "ml" prefix.

Here's the full catalog window of these folders and test files. Catalog window with copies of test file saved in other folders

This suggests a problem with the folder itself, but I'm not sure what. It has the same permissions as other folders at this level and above it.

  • 2
    Show the rest of the catalog window. If you placed the shapefile in a .gdb directory this is completely correct response to corrupting the file geodatabase.
    – Vince
    Commented Jul 15, 2020 at 0:34
  • 1
    Have you got all the files with precisely the same name? .shp, .dbf and .shx? Could you try saving as a new shapefile from Geopandas. There are shapefile repair utilities, the one I have used was released by Mountain Software but google can't find that one on the web. The question mark indicates that the geometry isn't defined, the repair utilities should resolve that. Commented Jul 15, 2020 at 0:34
  • Thanks for the ideas @MichaelStimson and Vince. I edited the original post to address them.
    – ChrisM
    Commented Jul 15, 2020 at 17:21
  • @MichaelStimson and Vince, I am currently working around this issue by saving to another folder, but want to understand what is causing this issue in this particular folder, if you have any other ideas. Thanks.
    – ChrisM
    Commented Jul 15, 2020 at 23:32
  • Downloaded or supplied data can have all sorts of problems, there is no single solution that will fix all problems, over time exposure to bad incoming data will equip you with a toolset of fixes. I started doing GIS even before shapefiles existed so I have a long menu of possible fixes, if I were to take a stab in the dark I'd say it could be the CPG or XML file that is causing the problem, these are safe to delete (keep a backup just in case), the data (shp, dbf and shx) doesn't seem to be corrupt if another package can read them properly. Commented Jul 16, 2020 at 0:33

1 Answer 1


The problem might be the name of your shp. As far as I know ArcGIS has a problem reading spaces and "-". Maybe try renaming your file.

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