The File Extensions Database

.BK1 File Extension

  • Developer by: Autodesk
  • Category: Backup Files
  • Format: Binary

What is an .BK1 file?

.BK1 is Autodesk Backup File

Backup file created by Autodesk products, including AutoCAD Mechanical, Mechanical Desktop, and AutoCAD Map; stores a .BAK file that has been renamed with the ".bk1" extension; renamed when the Autodesk program terminates unexpectedly.

BAK files are automatically created when users save drawing files. Therefore, when a program crashes, Autodesk applications try to rename the BAK file to BK1 to prevent a corrupted drawing file from replacing the original backup.

NOTE: If the BK1 extension is already in use, Autodesk programs use ".bk2" through ".bk9," as well as ".bka" through ".bkz" and ".baa" through ".bzz" until a unique extension is found.

Programs that open Autodesk Backup File
Autodesk AutoCAD 2018
Autodesk AutoCAD Mechanical 2018
File Type 2 Windows Indexing Service File
Developer by: Microsoft Category: System Files Format: Binary

File created by Indexing Service, a component of Windows used to automatically index file system search information; contains information used for making fast file searches in Windows; typically seen with the name propstor.bk1.

BK1 files are often located within the C:\System Volume Information\catalog.wci\ directory. Other catalog index files in this directory may include .BK2, .PS1, .PS2, .FID, .000, and .HSH files.

NOTE: Windows may also create BK1 files on external drives, such as USB flash drives.

Programs that open Windows Indexing Service File
Microsoft Windows
File Type 3 ERwin Backup File
Developer by: CA Category: Backup Files Format: Binary

Backup file created by ERwin Data Modeler, a data modeling program; contains a backup of a .ER1 diagram file; created automatically by ERwin when the ER1 file is opened; used to recover a data model file if the original becomes corrupted.

BK1 files are used by older versions of ERwin Data Modeler.

How to solve problems with BK1 files

  • Associate the BK1 file extension with the correct application. On :
    Windows: Right click on any BK1 file and then click "Open with" > "Choose another app". Now select another program and check the box "Always use this app to open *.BK1 files". Mac: Right click (or Ctrl-click) the BK1 file, then click "Open with" > "Other...". Then choose another program and check the "Always Open With" box. Linux: Right click on the file, and select "Open with" and choose another program. iPhone: Tap the file. If you do not see an app to open the file, then tap Share "Share" and choose an app. Alternatively, save the file. Then open the Files app Files app. There long-press on the file, then release your finger. You will see a black menu bar. Then tap "Share" and select an app. Android: Tap the Settings icon on your smartphone, then tap on the Apps section. There tap the Options icon in the top right-hand corner of the screen to change the default apps.
  • Update your software that should actually open .BK1 is Autodesk Backup File. Because only the current version supports the latest BK1 file format. Search, therefore, e.g. on the Autodesk manufacturer website after an available .BK1 is Autodesk Backup File update.
  • To make sure that your BK1 file is not corrupted or virus-infected, get the file again and scan it with antivirus software.