script and guide for getting duplicacy running on Windows
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backup_duplicacy.ps1 initial commit Nov 18, 2017
filters initial commit Nov 18, 2017

Duplicacy Backups

This is a document about setting up and running duplicacy for automated backups to local and cloud destinations on Windows.

The script here will run automated backups--you'll need to make some simple modifications to it. The tasks you need to do are:

  1. Install duplicacy and add it to your path
  2. Modify script with your own backup destinations, log file paths, duplicacy executable, etc.
  3. Open an account with a cloud backup provider (this document assumes backblaze b2)
  4. Initialize the backup locations per this document
  5. Run a backup manually per this document, if using encryption (the first time you run a backup for a location you're asked to type your encryption key--after that it's saved in the duplicacy config folder)
  6. Create a windows scheduled task to run at some interval with elevated privileges
  7. If you're backing up a user profile on Windows, see the "filter" section below.

These are "plug and chug" instructions for making encrypted backups to a local folder, and then copying those to a cloud storage provider.

Initialize a backup location

Local Backup

cd c:\users\myuser
duplicacy init local_C N:\_duplicacy_backup -e

(you'll be asked for an encryption password--type it manually)

This will:

  • make c:\users\myuser the folder that is backed up
  • give these backups the name local_C (to distinguish them from other backups in the same location)
  • set the backup destination to \N:_duplicacy_backup
  • encrypt the backups with the password you specify

Remote Backup

cd c:\users\myuser
duplicacy add -copy default b2 local_C b2://duplicacybucket1234

(you'll be prompted for your backblaze B2 credentials)

This will:

  • make the new storage location compatible with the existing one (-copy default)
  • give the new storage location the friendly name 'b2' (used when operating on it with certain commands)
  • give these backups the name local_C (to distinguish them from other backups in the same location)
  • specify the remote backup destination as a Backblaze B2 bucket with the name 'duplicacybucket1234'
  • my testing indicates not specifying -e here means your cloud backups are not encrypted. Not sure how/why that works just yet.

to run remote backup

dup copy -to b2 -threads 10

(copies local storage to b2)

To backup

The script will handle this, but it's good to be able to run a manual backup and to understand what's happening

To run the local backup:

cd c:\users\myuser
duplicacy backup -stats -vss

This will:

  • Run backups for c:\users\myuser
  • Use the Windows Volume Shadow Copy Service (VSS) to back up open files. Note you need be running an administrator command prompt to use the vss option.
  • Display stats on what is happening

To run the remote backup:

cd c:\users\myuser
duplicacy copy -to b2 -threads 10

This will:

  • Copy the backups for c:\users\myuser from your local storage to the remote storage 'b2' you added earlier.
  • Use 10 separate threads for uploading files (you might use more or less depending on your computer and connection capabilities)


The following statements will, roughly:

  • delete backups over a year old,
  • keep 1 snapshot a month for the last year
  • keep 1 snapshot a week for the last month
  • keep 1 snapshot a day for the last week
duplicacy prune -keep 0:365 -keep 30:30 -keep 7:7
duplicacy prune -keep 0:365 -keep 30:30 -keep 7:7 -storage b2
duplicacy prune
duplicacy prune -storage b2

The pruning process collects things to be deleted on the first run, and then actually deletes them when its run again. Although it seems like the second run is frequently hesitant to delete things--I guess that's better than the alternative.

To prune a specific snapshot:

duplicacy prune -r 45 -exclusive

This will:

  • prune snapshot 45


If restoring to a different folder (say on a new computer), then in the folder you want to restore to:

cd c:\myrestore
duplicacy init local_C N:\_duplicacy_backup -e 

(supply your encryption password)

OR you could init your remote storage:

duplicacy init local_C b2://duplicacybucket1234

(if you didn't initialize your remote with -e, don't include it here)


duplicacy list

This will show a list of snapshots

to restore:

duplicacy restore -r 10

This will restore snapshot 10 from default (local) storage

duplicacy restore -r 10 -storage b2

This will restore from storage called b2, if available


Windows profiles contain a lot of stuff that doesn't really need to be backed up. This repository includes a filter file that can help with that.

Put the "filters" file in the duplicacy config folder in the root of your profile (c:\users\myuser.duplicacy). This has a number of exclusions for temporary and generally useless files. Note: A number of the exclusions are drawn from the list of exclusions that Code42 published for the now defunct Crashplan Home service (

Make sure the filters are appropriate for your purposes--they may be too aggressive for some people.


To verify a specific snapshot:

duplicacy check -r 88 -files -stats

This will:

  • verify all backup files references by snapshot 88 existing
  • display what's happening
  • verify the integrity of each backup file (technically, it's verifying chunks--the duplicacy storage files, not the actual files that are backed up)

You could do

duplicacy check -r 88 -files -stats -storage b2

To run the check on your remote storage. The verification might end up costing transactions. I haven't tried it.

Using the Backup Script

  • The log file location needs to be created manually
  • Run a backup manually per this document, if using encryption. The first time you run a backup for a location you're asked to type your encryption key (the script doesn't do this)--after that it's saved in the duplicacy config folder.
  • The script assumes you are backing up to a local drive and then to a remote location. It may need some light editing if you only do local or remote backups.