Applies to: COMSOL Model Manager Versions: All versions

Problem Description

When trying to connect to my local Model Manager I receive an error message that says Failed to connect to Apache Solr


The most likely cause for this error message is that the index used by the Model Manager search functionality has become corrupt. This may happen, for example, if COMSOL Multiphysics is abruptly killed when it is in the process of updating the index.

It can also happen if the local Model Manager database is stored in a cloud drive that uses two-way-synchronization to copy data back and forth between the local file system and a remote cloud storage provider. Please note that storing a local Model Manager database on cloud drives that use such two-way-synchronization is not supported, and starting with update 2 for COMSOL Multiphysics 6.0 you will also get a warning if such a drive is detected when creating a new database. See this entry for more information.

The search index can be repaired following the steps below:

  • Copy the database directory and all its contents to a local folder on the computer that is not subject to two-way synchronization.

  • Open the Model Manager workspace in COMSOL Multiphysics.

  • Click the Databases tab.

  • Open the Databases Window.

  • Select the problematic database in the tree.

  • Delete the database configuration (the database file itself is not deleted).

  • Exit any running COMSOL Multiphysics instance.

  • In the copy of the problematic database on your local file system, rename the folder indexes to indexes2. (For Version 6.0, this folder was called index rather than indexes. So if you are using that version, do the same operation with the folder called index.)

  • Create a new empty folder with the name indexes (i.e., in the old ones' place).

  • Start COMSOL Multiphysics again and add the database via File menu > Open From > Add Database > Open Local Database and browse to the copied database file (.mphdb) on your local file system.

  • When COMSOL Multiphysics connects to the local database, the index will be automatically rebuilt (this will take some time depending on the size of the database). If successful, you can then delete the directory index2.