Mapdb Errors in PaperCut

KB Home   |   Mapdb Errors in PaperCut

Q Help! I canít access PaperCut and Iím seeing the following (or similar) error notification in my browser:

Error description: Checksum does not match, data broken 
Error details: Checksum does not match, data broken

at org.mapdb.Store.deserialize(
at org.mapdb.StoreDirect.get2(
at org.mapdb.StoreWAL.get2(
at org.mapdb.StoreWAL.get(
at org.mapdb.Caches$HashTable.get(
at org.mapdb.EngineWrapper.get(
at org.mapdb.HTreeMap.recursiveDirCount(
at org.mapdb.HTreeMap.sizeLong(
at org.mapdb.HTreeMap.size(

Errors like these typically pertain to configuration stores PaperCut uses called MapDB files. The trouble begins when the application is in the middle of writing to these files and canít gracefully finish the operation due to an unexpected stop or restart. The contents of these files aren’t too important since they are transitory in nature. MapDB files essentially backup of all the current connections PaperCut had open at the time the service started.

Thatís nice to know, but how do I fix this?

Here are the steps to follow:

  1. Stop the PaperCut Application server service. Follow the steps here on how to do this.
  2. Delete all files in the [app-path]\server\tmp directory.
  3. Move all mapdb files in [[app-path]\server\data\internal to a different directory.
  4. Restart the PaperCut Application Server service.

PaperCut will then create a new set of MapDB files after the restart, and you should be back up and running again.

If our advice doesn’t pan out, it might be an indication of a deeper database issue, and in that scenario, please give our support team a call directly so we can investigate.


We rectified this behavior in our 18.3.6 release (detailed as a known issue here). So, if you are reading this itís because you are hopefully running a version of PaperCut prior to 18.3.6.

Keywords: mapdb


Share your findings and experience with other PaperCut users. Feel free to add comments and suggestions about this Knowledge Base article. Please don't use this for support requests.

Article last modified on October 21, 2019, at 03:31 AM
Printable View   |   Article History   |   Edit Article