...
Verify that MobileMap licensed - MobileMap must be licensed to display base maps. If it is not licensed, or if the license has expired or is not valid, you should see a brief popup message when MobileMap starts up that indicates that the license was not found or is not valid. The best way to check, however, is to use the license tool (Actions > License Device). At the top of this tool you should see a message indicating the license status. If the license has expired simply re-submit to refresh your licenses. If you have never licensed your device, follow instructions here MobileMap: Installation and Licensing and hereMobileMap: Application Licensing
Verify that the data directory is correct - Base maps are stored in a data directory, typically on a MicroSD card, and MobileMap must have access to that directory. Use the Select Data Directory tool (Actions > Select Data Directory) to select the data directory. See instructions here MobileMap: Installation and Licensing. Note that the directory selected during this process should be the MobileMap root directory, and should not contain TPK or Shapefiles directly within it. The MobileMap root directory is typically named ‘MobileMap’ and should have a subfolder named ‘default’ and will likely have other folders like ‘Export’ and ‘Photos’.
Verify that your MobileMap folder structure is correct. MobileMap uses project or map cache folders which can be named however you want, but we recommend avoiding spaces or special characters in folder names. Project folders are found in the MobileMap root directory. Each project folder will have subfolders including ‘TPK’ and optionally ‘SHP’.
Verify that the base map you downloaded was successfully copied into the correct subfolder. The Download Basemap tool saves all downloaded TPK files into the devices Download folder. This is due to some limitations on file saving on some devices. This requires users to manually copy downloaded files to the correct TPK folder in their desired project folder. Use your devices file manage (e.g., ‘My Files’ on Samsung, ‘Files’ on Google Pixel, etc.) to copy files between folders. For example, if you are working on a project called ‘MyProject’, you will copy the TPK that you download from internal storage/Download → SD Card/MobileMap/MyProject/TPK.
Verify that the correct project has been selected. Use the Select Map Cache tool select the project or map cache where you saved your TPK. See instructions here MobileMap: Basic Operation
Verify that the TPK is enabled for display in display properties. Use the Select Layer Display Properties and verify that the TPK is visible in the list (should be near the bottom or the layers list) and that the checkbox is checked. See instructions here MobileMap: Basic Operation
Verify the extent of the base map you downloaded. MobileMap uses the first loaded map cache to set the maximum map extent. If the first loaded base map (e.g., TPK) is small and not in your area of interest, you will be unable to pan the map to your current extent, thus your new base map will not be visible. MB&G WSG recommends creating a single large area, low resolution base map and storing it in the default folder (e.g., SD Card/MobileMap/default/TPK) which can be used by MobileMap to set a large map extent when it is loading base maps.
Verify the zoom level of the base map you loaded. Base maps downloaded within MobileMap have a maximum scale or zoom level applied to them. See the question Why does my Base Map disappear when I zoom in? for more details on this problem. If you have made it to this step, then it is possible that you are simply too far zoomed in for your base map to display. Try zooming out - way out - and see if your base map shows up. If so, use the approaches described above or in this document MobileMap: Base Map Creation for MobileMap to address this issue.
...
If the problem does still exist (scenario 2) then it can be helpful to export the MobileMap database and try to manually add the data to the feature layer. Using this manual approach, you may see a more detailed error that will help you understand what the data problem is and how to resolve it. If not, reach out to MB&G WSG support team to help resolve.
Once the source of the issue has been resolved, the duplicates will need to be removed. Start detecting the duplicates by looking for features with exact matches in their Unique_ID field. You can review these using ArcPro or other tools, or using a ‘find duplicates’ tool that MB&G WSG can enable on your InventoryManager (or other Spatial CMS) site. When enabled, this tool performs a statistical query of a feature layer to find all Unique_ID values with more than one instance, and retrieves the OBJECTIDs for all but the last instance. These OBJECTIDs can then be used to delete the duplicates.
...