Frequently Asked Questions (FAQs)
These FAQs aim to help you understand HashOnClick better, and quickly solve any difficulties that you might encounter.
Q: What is an SHA-1 hash value?
A: An SHA-1 hash value is a 40-character string that identifies the contents of a file. If two files have the same contents then it's guaranteed they will have the same SHA-1 hash value.
Q: What is an MD5 hash value?
A: An MD5 hash value is a 32-character string that identifies the contents of a file. If two files have the same contents then it's extremely probable they will have the same MD5 hash value.
Q: What is a CRC32 hash value?
A: A CRC32 hash value is an 8-character string that identifies the contents of a file. If two files have the same contents then they will probably have the same CRC32 hash value. The Zip format uses CRC32 values to verify the contents of files.
Q: Why do you support 3 different ways of doing the same thing?
A: In some cases you may want the CRC32 value, e.g. when comparing with files in a Zip file or with files on an FTP server that can only return CRC32 values. MD5 values are commonly used on web sites and are supported by a few FTP servers. SHA-1 values are more accurate and are becoming more a popular choice instead of MD5 values.
Q: Is it possible that the CRC32, MD5, or SHA-1 values may be the same for two files even though the file contents are different?
A: With CRC32 is unlikely, but not impossible. With MD5 it's highly unlikely, but in some cases but may be possible. With SHA-1 it's impossible (at time of writing).
Q: What type of files can I get the hash values for?
A: Any type of file. Folders do not have contents so it cannot be used with folders.
Q: Why does your hash value not match the hash value I got from another program for the same file?
A: There are many hash calculation programs available, but unfortunately not all of them have been tested as much as HashOnClick. It may also be that they have incorrectly labeled the hash algorithm, e. g. they may say SHA when it may be SHA-2 512bits.
Q: I'm getting the error "Cannot open file" whenever I try and get the MD5 or SHA-1 value of a file.
Q: I'm getting the error "Failed" whenever I try and get the CRC32 value of a file.
A: The most probable reason for this error is that you don't have access rights to the file, or it cannot be opened because it is being used by another program, process, or Windows itself.
Q: Windows Explorer has stopped functioning. Why?
A: It is not possible to use Windows Explorer when HashOnClick is in use. Simply close the HashOnClick window and Windows Explorer will function normally.
Q: Does HashOnClick work with 64-bit versions of Windows?
A: The Windows context menu does not work with HashOnClick (as HashOnClick is a 32-bit program, and not 64-bit). However, the command line version of HashOnClick (HOC.exe) works with both 32-bit and 64-bit versions of Windows.
Q: I have a multi-core/multi-CPU system. Does HashOnClick make full use of this?
A: Yes. HashOnClick V2.2 and later is multi-threaded, meaning it will read the file at the same time it is calculating its hash value. Because of this it is one of the fastest hash calculation programs available today on Windows systems.