<title>VeraCrypt - Free Open source disk encryption with strong security for the Paranoid</title>
<metaname="description"content="VeraCrypt is free open-source disk encryption software for Windows, Mac OS X and Linux. In case an attacker forces you to reveal the password, VeraCrypt provides plausible deniability. In contrast to file encryption, data encryption performed by VeraCrypt is real-time (on-the-fly), automatic, transparent, needs very little memory, and does not involve temporary unencrypted files."/>
Make sure you use the latest stable version of VeraCrypt. If the problem is caused by a bug in an old version of VeraCrypt, it may have already been fixed. Note: Select
<emstyle="text-align:left">Writing/reading to/from volume is very slow even though, according to the benchmark, the speed of the cipher that I'm using is higher than the speed of the hard drive.</em></div>
First, make sure that your VeraCrypt container does not have a file extension that is reserved for executable files (for example, .exe, .sys, or .dll). If it does, Windows and antivirus software may interfere with the container and adversely affect the performance
Second, disable or uninstall any application that might be interfering, which usually is antivirus software or automatic disk defragmentation tool, etc. In case of antivirus software, it often helps to turn off real-time (on-access) scanning in the preferences
of the antivirus software. If it does not help, try temporarily disabling the virus protection software. If this does not help either, try uninstalling it completely and restarting your computer subsequently.</div>
<emstyle="text-align:left">VeraCrypt volume cannot be mounted; VeraCrypt reports "</em>Incorrect password or not a VeraCrypt volume<emstyle="text-align:left">".</em></div>
<emstyle="text-align:left">After successfully mounting a volume, Windows reports "</em>This device does not contain a valid file system<emstyle="text-align:left">" or a similar error.</em></div>
You can use filesystem repair tools supplied with your operating system to attempt to repair the filesystem on the VeraCrypt volume. In Windows, it is the '<emstyle="text-align:left">chkdsk</em>' tool. VeraCrypt provides an easy way to use this tool on a VeraCrypt
volume: First, make a backup copy of the VeraCrypt volume (because the '<emstyle="text-align:left">chkdsk</em>' tool might damage the filesystem even more) and then mount it. Right-click the mounted volume in the main VeraCrypt window (in the drive list)
and from the context menu select '<emstyle="text-align:left">Repair Filesystem</em>'.</div>
<emstyle="text-align:left">When trying to create a hidden volume, its maximum possible size is unexpectedly small (there is much more free space than this on the outer volume).</em></div>
Unlike the FAT filesystem, the NTFS filesystem always stores internal data exactly in the middle of the volume. Therefore, the hidden volume can reside only in the second half of the outer volume. If this constraint is unacceptable, do one of the following:</div>
Reformat the outer volume as FAT and then create a hidden volume within it. </li><listyle="text-align:left; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px">
If the outer volume is too large to be formatted as FAT, split the volume to several 2-terabyte volumes (or 16-terabyte volumes if the device uses 4-kilobyte sectors) and format each of them as FAT.
Defragment the outer volume (mount it, right-click its drive letter in the '<emstyle="text-align:left">Computer</em>' or '<emstyle="text-align:left">My Computer</em>' window, click
<emstyle="text-align:left">Properties</em>, select the <emstyle="text-align:left">
Tools</em> tab, and click '<emstyle="text-align:left">Defragment Now</em>'). After the volume is defragmented, exit
<emstyle="text-align:left">Disk Defragmenter</em> and try to create the hidden volume again.
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If this does not help, delete <emstyle="text-align:left">all</em> files and folders on the outer volume by pressing Shift+Delete, not by formatting, (do not forget to disable the Recycle Bin and System Restore for this drive beforehand) and try creating the
hidden volume on this <emstyle="text-align:left">completely empty </em>outer volume again (for testing purposes only). If the maximum possible size of the hidden volume does not change even now, the cause of the problem is very likely an extended root directory.
If you did not use the '<emstyle="text-align:left">Default</em>' cluster size (the last step in the Wizard), reformat the outer volume and this time leave the cluster size at '<emstyle="text-align:left">Default</em>'.</div>
If it does not help, reformat the outer volume again and copy less files/folders to its root folder than you did last time. If it does not help, keep reformatting and decreasing the number of files/folders in the root folder. If this is unacceptable or if it
does not help, reformat the outer volume and select a larger cluster size. If it does not help, keep reformatting and increasing the cluster size, until the problem is solved. Alternatively, try creating a hidden volume within an NTFS volume.</div>
In addition, the following error may be reported: "<emstyle="text-align:left">The process cannot access the file because it is being used by another process.</em>"</div>
This is probably caused by an interfering application. Note that this is not a bug in VeraCrypt. The operating system reports to VeraCrypt that the device is locked for an exclusive access by an application (so VeraCrypt is not allowed to access it).</div>
It usually helps to disable or uninstall the interfering application, which is usually an anti-virus utility, a disk management application, etc.</div>
<emstyle="text-align:left">In the VeraCrypt Boot Loader screen, I'm trying to type my password and/or pressing other keys but the VeraCrypt boot loader is not responding.</em></div>
Restart your computer, press F2 or Delete (as soon as you see a BIOS start-up screen), and wait until a BIOS configuration screen appears. If no BIOS configuration screen appears, restart (reset) the computer again and start pressing F2 or Delete repeatedly
as soon as you restart (reset) the computer. When a BIOS configuration screen appears, enable pre-boot support for USB keyboards. This can typically be done by selecting:
<emstyle="text-align:left">Enabled</em>. (Note that the word 'legacy' is in fact misleading, because pre-boot components of modern versions of MS Windows require this option to be enabled to allow user interaction/control.) Then save the BIOS settings (typically
by pressing F10) and restart your computer. For more information, please refer to the documentation for your BIOS/motherboard or contact your computer vendor's technical support team for assistance.</div>
<emstyle="text-align:left">After the system partition/drive is encrypted, the computer cannot boot after it is restarted (it is also impossible to enter the BIOS configuration screen).</em></div>
If the BIOS/motherboard/computer manufacturer/vendor does not provide any updates that resolve the issue and you use Windows 7 or later and there is an extra boot partition (whose size is less than 1 GB) on the drive, you can try reinstalling Windows without
this extra boot partition (to work around a bug in the BIOS). </li></ul>
<emstyle="text-align:left">After the pre-boot authentication password is entered during the system encryption pretest, the computer hangs (after the message '</em>Booting...<emstyle="text-align:left">' is displayed).</em>
<emstyle="text-align:left">When the system partition/drive is encrypted (partially or fully) and the system is restarted for the first time since the process of encryption of the system partition/drive started, the computer hangs after you enter the pre-boot
authentication password (after the message '</em>Booting...<emstyle="text-align:left">' is displayed).</em>
<emstyle="text-align:left">After the hidden operating system is cloned and the password for it entered, the computer hangs (after the message '</em>Booting...'<emstyle="text-align:left"> is displayed).</em>
Upgrade your BIOS (for information on how to do so, please refer to the documentation for your BIOS/motherboard or contact your computer vendor's technical support team for assistance).
Use a different motherboard model/brand. </li><listyle="text-align:left; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px">
If the BIOS/motherboard/computer manufacturer/vendor does not provide any updates that resolve the issue and you use Windows 7 or later and there is an extra boot partition (whose size is less than 1 GB) on the drive, you can try reinstalling Windows without
this extra boot partition (to work around a bug in the BIOS). </li><listyle="text-align:left; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px">
There two other known workarounds for this issue that require having a Windows Installation disk:
Boot your machine using a Windows Installation disk and select to repair your computer. Choose "Command Prompt" option and when it opens, type the commands below and then restart your system:
Delete the 100 MB System Reserved partition located at the beginning of your drive, set the system partition next to it as the active partition (both can be done using diskpart utility available in Windows Installation disk repair option). After that, run Startup
Repair after rebooting on Windows Installation disk. The following link contains detailed instructions:
<emstyle="text-align:left">When trying to encrypt the system partition/drive, during the pretest, the VeraCrypt Boot Loader always reports that the pre-boot authentication password I entered is incorrect (even though I'm sure it is correct).</em></div>
When you <emstyle="text-align:left">set</em> a pre-boot authentication password, remember whether the
<emstyle="text-align:left">Num Lock</em> and <emstyle="text-align:left">Caps Lock</em> keys are on or off (depending on the manufacturer, the keys may have different labels, such as
<emstyle="text-align:left">Num LK</em>). Note: You can change the state of each of the keys as desired before you set the password, but you need to remember the states.
<emstyle="text-align:left">When the system partition/drive is encrypted, the operating system 'freezes' for approx. 10-60 seconds every 5-60 minutes (100% CPU usage may co-occur).</em></div>
Try disabling all power-saving-related features (including any special CPU enhanced halt functions) in the BIOS settings and in the 'Power Options' Windows control panel.
Replace the processor with a different one (different type and/or brand). </li><listyle="text-align:left; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px">
Replace the motherboard with a different one (different type and/or brand). </li></ul>
Try disabling any antivirus tools, system "tweakers", and any other similar applications. If it does not help, try uninstalling them and restarting Windows.
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If the problem persists, run VeraCrypt and select <emstyle="text-align:left">Help</em>> '<emstyle="text-align:left">Analyze a System Crash</em>' shortly after the system crashes or restarts. VeraCrypt will then analyze crash dump files that Windows automatically
created when it crashed (if any). If VeraCrypt determines that a bug in a third party driver is likely to have caused the crash, it will show the name and provider of the driver (note that updating or uninstalling the driver might resolve the issue). Whatever
the results, you will be able to choose to send us essential information about the system crash to help us determine whether it was caused by a bug in VeraCrypt.
<emstyle="text-align:left">On Windows 7/Vista (and possibly later versions), the Microsoft Windows Backup tool cannot be used to backup data to a non-system VeraCrypt Volume.</em></div>
Mount the VeraCrypt volume to which you want to back up data. </li><listyle="text-align:left; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px">
Right-click a folder located on the volume (or right-click its drive letter in the '<emstyle="text-align:left">Computer</em>' list) and select an item from the '<emstyle="text-align:left">Share with</em>' submenu (on Windows Vista, select '<emstyle="text-align:left">Share</em>').
Follow the instructions to share the folder with your user account. </li><listyle="text-align:left; margin-top:0px; margin-bottom:0px; padding-top:0px; padding-bottom:0px">
In the Windows Backup tool, select the shared folder (the network location/path) as the destination.
<emstyle="text-align:left">The label of a filesystem in a VeraCrypt volume cannot be changed from within the 'Computer' window under Windows Vista or a later version of Windows.</em></div>
Close, disable, or uninstall all programs that might be using the partition/device in any way (for example an anti-virus utility). If it does not help, right-click the '<emstyle="text-align:left">Computer</em>' (or '<emstyle="text-align:left">My Computer</em>')
icon on your desktop and select <emstyle="text-align:left">Manage </em>-><emstyle="text-align:left"> Storage
</em>-><emstyle="text-align:left"> Disk Management.</em> Then right-click the partition that you want to encrypt, and click
<emstyle="text-align:left">Change Drive Letter and Paths. </em>Then click <emstyle="text-align:left">
Remove</em> and <emstyle="text-align:left">OK. </em>Restart the operating system.</div>
Close all applications that are using files on the outer volume. If it does not help, try disabling or uninstalling any anti-virus utility you use and restarting the system subsequently.</div>
Locate the <emstyle="text-align:left">IRPStackSize </em>key in the Windows registry and set it to a higher value. Then restart the system. If the key does not exist in the Windows registry, create it at
<emstyle="text-align:left">HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer\Parameters</em> and set its value to 16 or higher. Then restart the system. For more information, see:
Known Issues & Limitations</a>, <ahref="Incompatibilities.html"style="text-align:left; color:#0080c0; text-decoration:none; font-weight:bold.html">Incompatibilities</a></p>
