Applies to: Mobile Mapping Systems (VLX and M6)

Problem description

Users might face an error from VLX UI immediately after starting the application.

The error message is the following:

Oops, an error occurred!

ERROR: An error occurred in the frontend:
Uncaught (in promise): Backend returned error 'The directory '/srv/data/datasets rec' does not exist. - Did you plug the SSD drive into its slot?'


Possible causes and fixes

Cause 1: SSD drive incorrectly puggled

Make sure the SSD is correctly plugged into the slot on the device.


Cause 2: datasets_rec folder is deleted


The following instructions make use of Ubuntu's terminal on the VLX or M6. If you are unexperienced in using it, please reach out to NavVis Support instead.

As described directly from the error message, the datasets_rec folder in which the mapping data is recorded, is missing under /srv/data. For example:

Possible fix

The SSD drive will be mounted under /srv/. Please execute the following fixes only on the VLX and M6 device itself. On workstations the SSD can be mounted under other paths.

Check under /srv/ to see if data/datasets_rec folder exists. If not, one can create the datasets_rec folder manually, either using the terminal or the GUI. Remember to set up the permissions correctly for the data folders:

  1. Create a folder manually in terminal.

mkdir -p /srv/data/datasets_rec

  1. Add the correct permissions to the folder.

sudo chmod -R 755 /srv/data

  1. Check if the /srv/data folder exists. If not, one can also use the command nv_setup-data-disk, which will automatically set up the essential folder structures, as well as the permissions. Example of usage:

sudo nv_setup-data-disk /srv -y


Written in May 2022