Symptoms

1. You make an entire machine backup or disks/volumes backup of a machine with Agent for Linux
2. Backup fails with the following error:

   No volumes have been found while processing the 'All Volumes' template.

   or

   No volumes have been found while processing the 'Fixed Volumes' template
    
   or
   The SnapAPI kernel module is not loaded for the kernel currently running on the system. Install the module for this kernel version, and then retry the backup.
   Error code: 101
   Module: 149
   LineInfo: 0x14525B055CC9B598
   Fields: {"$module":"disk_bundle_lxa64_14330"}
   Message: The SnapAPI kernel module is not loaded for the kernel <version>-default that is running in this system. Install the module for this kernel version, and then retry the backup.

Cause

The SnapAPI kernel module is not loaded for kernel version currently running on the affected system. This error usually occurs after kernel update.

If there has been no successful backups since the installation of the product, the snapapi module could have been incorrectly installed or not installed at all.

Solution

First, install the kernel sources that exactly match your kernel version: see product documentation for instructions.

After installing the necessary sources, repeat Agent for Linux installation on the machine.

If this does not resolve the issue, collect system information from the affected machine and contact Acronis Support with reference to this article.

If the product fails with "The SnapAPI kernel module is not loaded for the kernel 4.15.0-121-generic that is running in this system. Install the module for this kernel version, and then retry the backup." after a kernel update, the module was not rebuild correctly during the update. When a new kernel is installed and system reboots, dkms_autoinstaller tries to automatically build modules for a new kernel. If the module is not present after the reboot, dkms_autoinstaller either did not start or failed to build modules. To avoid this issue, you need to install kernel-devel package when updating kernel.

If the product fails with "The SnapAPI kernel module is not loaded for the kernel 4.18.0-193.19.1.el8_2.x86_64 that is running in this system. Install the module for this kernel version, and then retry the backup" on CentOS 8.2 with enabled secure boot, the issue is caused by Bug 1861977 confirmed by Red Hat. As workaround for the issue, downgrade grub2 and its dependencies:
yum downgrade grub2* shim* mokutil