Frequently asked questions

I want to use more then one backup server. What do I have to consider?

For security reasons the UrBackup Client only allows the backup server it first sees to download files. This is even the case if you update the Client. To select a different backup server you have to edit server_idents.txt in the directory where you installed UrBackup Client. To authenticate an additional backup server you have to ask the server administrator for the server key (It is shown on the status page) and add this key as an additional row to the server_idents.txt. Another option is to use the same key and private/public key pair for all backup servers (The private/public key pair is present starting from UrBackup Server 1.4 as urbackup/server_ident.priv and urbackup/

Server says 'Server rejected' for a client and does not backup that client

Because of security reasons the UrBackup client only allows the first UrBackup server it sees to back up. For this reasons every server has a random server identity and starting from UrBackup Server 1.4 a private/public key pair. This identity changes if you uninstall and then install the server or if you use another server. The best option is to prevent this by saving the urbackup/server_ident.key, and if present urbackup/server_ident.priv, urbackup/server_ident_ecdsa409k1.priv, urbackup/ and urbackup/, on the server and to restore it if it has changed. If you did not do this your options are:

With newer UrBackup versions the identity files are also automatically backed up the the backup storage (“urbackup” sub-folder) if the nightly database backup is enabled.

The Client says the backup is done, but the server still works?

The modified files are copied as fast as possible from the client. Only afterwards the server examines the files and puts them into the right directory. This can take a long time and the client is not necessary for this any more. Because of this the Client already says the backup is done. Enabling the file entry cache in the advanced settings may speed up this process.

Where are the backups saved?

The backups are saved in the path you set during installation or in the web-interface. In this path there is one directory per client. Directly in this directory there are the image backups. They have the pattern Image_<Drive>_<YYMMDD-HHMM>.vhd. is the imaged partition. DD the date. MM the month. YY the year. HH the hour and MM the minute. The file backups are in subdirectories with the pattern `YYMMDD-HHMM` (see above for explanation). `current` is a symbolic link to the most current finished file backup. The backups are ordered chronological if you sort by file or directory name. In the directory 'clients' there are links to the most current file backup of each client.

I want to extract a file from the image backups. How do I do that?

The image backups are saved as VHD-files or compressed VHD-files. Those are standardized (by Microsoft) virtual disk container formats. Microsoft Virtual PC and Windows XP Mode use the same file format. If you use one of these products you can simply add the image as an hard disk to the virtual machine. If the image is compressed (*.vhdz) you need to first uncompress the image. You can do that by executing C:\Program Files\UrBackupServer\uncompress_image.bat (Will ask for an image to uncompress). Windows 7 allows you to directly add the uncompressed VHD files as a hard disk in system settings->Manage->Computer management->Disk management->Other Actions -> Add Virtual Hard Disk. The image will appear as another drive in the explorer. You can then extract the file. This seems to only work if the image is on a local hard drive – you have to copy the image from the server on one of your hard disks. If you do not want to do this the (free) Gizmo Central can mount VHD files from network paths.

Always mount the images read only!

On Linux, starting with UrBackup Server 1.4, you can mount compressed or uncompressed images directly using fuse and the kernel NTFS driver. UrBackup Server must be build with ./configure --with-mountvhd. Then you can mount images via start_urbackup_server --mountvhd /path/to/image.vhdz --mountpoint /media/image.

Since UrBackup 2.1.x you can mount the image backups via web interface.

How to define a backup window?

In the settings you can set a backup window. The server will only start backing up clients within this window. The clients can always start backups on their own, even outside the backup windows. If a backup is started it runs till it is finished and does not stop if the backup process does not complete within the backup window. A few examples for the backup window:

1-7/0-24: Allow backups on every day of the week on every hour.
Mon-Sun/0-24: An equivalent notation of the above
Mon-Fri/8:00-9:00, 19:30-20:30;Sat,Sun/0-24: On weekdays backup between 8 and 9 and between 19:30 and 20:30. On Saturday and Sunday the whole time.

As one can see a number can denote a day of the week (1-Monday, 2-Thuesday, 3-Wednesday, 4-Thursday, 5-Friday, 6-Saturday, 7-Sunday). You can also use the abbreviations of the days (Mon, Thues, Wed, Thurs, Fri, Sat, Sun). The times can either consist of only full hours or of hours with minutes. The hours are on the 24 hour clock. You can set multiple days and times per window definition, separated per ",". You can also set multiple window definitions. Separate them with ";".

How to exclude files?

You can exclude files with wildcard matching. For example if you want to exclude all MP3s and movie files enter something like this:


If you want to exclude a directory e.g. Temp you can do it like this:

*/Temp/* (or *\Temp\*)

This would exclude all files in directories named Temp. You can also give the full local name


or the name you gave the location e.g. with C:|C_Drive


Rules are separated by a semicolon (";"). Use a backslash for Windows clients ("\") and a forward slash for Linux clients ("/") to separate folders.

See also the section on glob patterns for general syntax information for glob patterns.

How to include files?

If you do not define an include pattern all files in the backups paths except the excluded ones are backed up. As soon as you define an include pattern only files which match this pattern are backed up. Similar to the exclude pattern you can include files by their extension:


Would only backup Word documents.


Would only backup files in document folders.

Additionally to the standard wildcard("*") which matches every character you can use ":" which matches every character except the path separator (/ or \). If you backup e.g. the C:\Users path and want to backup all document directories you can use the pattern


That way e.g. Users\Foo\Other\Documents would not be backed up.

The pattern is used for all paths you specify. So if you use the above rule for the Users folder and want to backup all files in another folder be sure to add that folder to the pattern e.g. by specifying


See also the section on glob patterns for general syntax information for glob patterns.

Glob/wildcard patterns

Information about glob/wildcard patterns in UrBackup.

How to define a clean-up window?

UrBackup will do its clean-up during this time. This is when old backups and clients are deleted, the quotas are enforced, old database entries are deleted and the database is backed up. You can specify the weekday and the hour as intervals. The syntax is the same as for the backup window. Thus please see the FAQ entry of the <html>backup window</html> for details on how to specify such time windows. The default value is 1-7/3-4 which means that the clean-up will be started on each day (1-Monday - 7-Sunday) between 3 am and 4 am.

How to define default backup locations?

Just enter the different locations separated by a semicolon (";") e.g.

C:\Users;C:\Program Files

If you want to give the backup locations a different name you can add one with the pipe symbol e.g:

C:\Users|User files;C:\Program Files|Programs

gives the "Users" directory the name "User files" and the "Program files" directory the name "Programs".

Those locations are only the default locations. Even if you check “Separate settings for this client” and disable “Allow client to change settings”, once the client modified the paths changes in this field are not used by the client.

How to specify the volumes to backup?

UrBackup backs up all the volumes you specify in the “Volumes to backup” field. You should specify volume letters (C,D,E,…) separated by ";" or "," there. With UrBackup Client and Server 1.4 you can also sepecify "ALL" to backup all volumes or "ALL_NONUSB" to backup all volumes except volumes connected via USB.

##Microsoft Outlook .ost files aren’t backed up! Microsoft Outlook adds exceptions to the Microsoft Shadow Copy Service to exclude the .ost files. Several Backup tools (UrBackup included) therefore do not backup them. Here is what seems like an official statement from Microsoft: “Maintaining changes to .ost files within shadow copies is expensive in terms of space and I/O activity. The performance impact doesn’t occur during the image backup itself–the only extra work at backup time is backing up the .ost file as part of the image. Instead, the performance impact occurs during the ongoing, everyday I/O to the .ost file when Outlook is running. If the .ost changes were kept in shadow copies, then every time Outlook writes to the .ost file, the result is a copy-on-write I/O hit (2 writes, 1 read). Although we have worked to reduce the impact of copy-on-writes on shadow copies, a heavily churned file like an .ost file could still cause problems. For these reasons, and the fact that .ost files can be regenerated, we chose to delete .ost files from the shadow copy before the image is created. Even if the performance issues didn’t exist, there are situations where Exchange will, after an .ost is restored, detect a “future” version of the .ost file and force you to delete and then regenerate the local .ost file. Therefore, it’s still preferable to regenerate an .ost file instead of restoring it.”

Basically just backup the Exchange server (which you can do with UrBackup, too) and you are good.

What does the "Archived" column show?

If the box in that column is checked the backup is archived. As long as a backup is archived UrBackup won’t delete it under any circumstance. If there is a stop watch next to the box it means the backup will stop being archived after some time. This time is shown if you hover over the stop watch.

How to use the archive window?

The archival window allows you to archive backups at very specific times. The format is very similar to crontab. The fields are the same except that there are no minutes:

Field Allowed values Remark
Day of month1-31 
Month1-12No names allowed
Day of week0-70 and 7 are Sunday

To archive a file backup on the first Friday of every month we would then set “Archive every” to something like 27 days. After entering the time we want the backups archived for we would then add


as window (hour;day of month;month;day of week). To archive a backup every Friday we would set “Archive every” to a value greater than one day but less than 7 days. This works because both conditions have to apply: The time since the last backup archival must be greater than “Archive every” and the server must be currently in the archive window. Other examples are easier. To archive a backup on the first of every month the window would be


and “Archive every” something like 2-27 days. One can add several values for every field by separating them via a comma such that


and “Archive every” one day would archive a backup on Wednesday and Friday. Other advanced features found in crontab are not present.

What is the global soft filesystem quota?

During clean-ups UrBackup will look at the used space of the filesystem the backup folder is on. If the used space is higher than the global soft filesystem quota UrBackup will delete old backups, if possible, till the used space is below the quota. Be aware that not only UrBackup’s files count against the quota, but other files as well. A quota that only takes into account UrBackup’s files is the client specific quota. You can specify the quota via a percentage of total space, or by a size. For example let the size of the Backup device be 1 Tera-byte: If you set the global filesystem quota to “90%”, UrBackup will delete old backups as soon as more than about 900 Giga-bytes of the available space is used. You could also directly set the quota to 900 Giga-bytes by setting it to “900G”. Other units are possible, e.g. “900000M” or “1T”.

Open files in TrueCrypt/VeraCrypt volumes are not backed up!

See no shadow copies on TrueCrypt/VeraCrypt volumes.

How to backup from or to file shares or mapped network drives on Windows

If you want to backup from or to file shares or mapped network drives on Windows there are some limitations and caveats you have to keep in mind.

Change the user UrBackup runs as

  1. Go to the service configuration utility by e.g. WINDOWS+R “services.msc”. Right-click “UrBackup Client Service for Backups” or “UrBackupServer” and select properties.
  2. In the “Log on” tab select the required user. You will have to configure a password if the user currently does not have a password. See next section on how to configure a password for the Administrator account.
  3. Restart the computer or the service.

Configure a password for the Administrator account and supply credentials

  1. In an elevated command prompt type in and run net user Administrator /active:yes
  2. In the user account settings click “Manage another account” and configure a password for the Administrator.
  3. Switch your user to “Administrator” (you have to enter the configured password). Access the target network share. Click save when asked for credentials.

UrBackup has an error that the "base dir" is lost during a file backup or that the "access to root directory is gone"

UrBackup does consistent backups by creating snapshots of the volumes the files reside on (also called shadow copies). Once a snapshot is created, when data is written to the volume (for example if a file is changed) the old data has to be copied to the so called shadow storage in order to preserve the point in time snapshot. If too much data is overwritten the volume may not have enough space to save the data being overwritten for the existing snapshot. In this case Windows deletes the snapshot and UrBackup stops the backup and has to start anew. You can confirm this is happening by looking into the Windows event log for “VSS” error events.

To prevent this issue you should:

Windows Encrypted File System (EFS) files are not backed up?

Windows EFS files can be backed up while they are still encrypted or unencrypted. UrBackup file backup only supports the latter. (The image backup backs up the EFS files encrypted.) In order to open EFS files the Windows user accessing the file needs the EFS certificate. The UrBackup client runs per default as “LOCAL SYSTEM” user which does not have any EFS certificate. To enable EFS backup you can run the UrBackup background server as a different user which has access to the relevant EFS certificates. This should still be a administrator account.

Change the user UrBackup client background service runs as

  1. Go to the service configuration utility by e.g. WINDOWS+R “services.msc”. Right-click “UrBackup Client Service for Backups” and select properties.
  2. In the “Log on” tab select the required user. You will have to configure a password if the user currently does not have a password.
  3. Restart the computer or the service.

Afterwards you should run a full file backup.

How to import or seed remote client via non-networked disk transfer

See how to import or seed remote client via non-networked disk transfer.