ClamXav, the free virus scanner for Mac OS X, received a fresh update today featuring a bunch of tweaks and fixes, and a new ClamAV engine (the heart and soul of the app that helps it keep your Mac healthy and secure). Thanks to the ClamAV open source antivirus engine, ClamXav has the ability to detect. If you must have one, I would recommend ClamXav. It's not particularly fast, but no AV software is worth paying for on OS X. I will warn you to stay away from Norton AV, since there software seems to slow computers down. ClamXav is an open source AV scanner for OS X based on the popular UNIX ClamAV virus engine. ClamXAV is an anti-malware solution for macOS which uses the popular ClamAv antivirus engine, and designed to detect and quarantine all kids of threats (for both Mac and Windows) such as viruses, trojans, phishing and spyware. Robust antivirus solution with a clear-cut user interface and real-time.

I'm running ClamXav Sentry as 'launch agent' with ClamAV antivirus scanning engine of my own custom build.
I've tested for building ClamAV (from version 0.90.x to version 0.103.x) on Mac OS X 10.4 through macOS 11.0 Big Sur.
I'm running the latest stable release ClamAV 0.103.0 on macOS 11.0 Big Sur now.
ClamAV 0.103.0 is available on the Download page of ClamavNet, and the release note is here!
When you want to build ClamAV-devel from the Git sources, autotools are now requied.
For further information, see the following section:
'How to install ClamAV®-devel from the Git sources on macOS'.

This memorandum contains as below:
・ Memorandum 1: Building ClamAV 0.103.x on OS X 10.10 Yosemite through macOS 11.0 Big Sur
・ Memorandum 2: Building ClamAV 0.99.x on OS X 10.10, 10.11, 10.12 and macOS 10.13 High Sierra
・ Memorandum 3: Building ClamAV 0.98.7 on OS X 10.10 Yosemite and 10.11 El Capitan
・ Memorandum 4: Building ClamAV on Mac OS X 10.4 (Intel)
・ Memorandum 5: Building ClamAV on Mac OS X 10.4 (PPC)
・ Memorandum 6: Building ClamAV on Mac OS X 10.6 through OS X 10.9 Mavericks
・ Memorandum 7: Running clamd and freshclam as daemon
・ Memorandum 8: Running ClamXav Sentry as 'launch agent' on Mac OS X 10.6 and later…
・ Memorandum 9: Update ClamXav's own Virus Database and running RunFreshclam as daemon
・ Memorandum 10: Running ClamXAV version 2.18.x with B.Y.O. ClamAV antivirus scanning engine
・ Links…


1. Requirements to build ClamAV 0.103.x is very much the same as building ClamAV 0.102.x.
2. Requirements to build ClamAV 0.102.x are almost the same as building ClamAV 0.101.x. and ClamAV 0.100.x.
The differences are as follows:
LLVM current version is 10.0.x, though ClamAV 1.02.x supports only LLVM =< 3.6.x.

Clamxav For Mac Os X 10.10

The ClamAV team is not maintaining repackaged LLVM now, and they may drop the repackaged LLVM entirely
and deprecate support for system-installed LLVM in favor of the bytecode interpreter.
So LLVM Libraries are not necessarily required to build ClamAV 0.102.x, I think.
I am now configuring ClamAV 0.102.x to disable LLVM as follows:
Of course you can configure ClamAV 0.102.x to enable LLVM as before:
3. Requirements to build ClamAV 0.102.x and ClamAV 0.101.x are almost same as before.

4. Differences



ClamAV 0.99.x contains major new features such as YARA rules, PCRE - Perl Compatible Regular Expressions and so on.
To support YARA and ClamAV logical signatures, the Perl Compatible Regular Expressions (PCRE) library is required.
If PCRE isn't installed on your system, you will get a warning message like this while running freshclam.
1. To ensure the PCRE library:
1) Install PCRE - Perl Compatible Regular Expressions.,

2) When compiling ClamAV 0.99.x, it fails with an error:

3) To avoid this failure, simply set CPPFLAGS:
4) And add this configuration option when configuring ClamAV: --with-pcre=/usr/local/pcre2.
2. To compile ClamAV 0.99.x on OS X 10.10 Yosemite or on OS X 10.11 El Capitan and macOS 10.12 Sierra,

3. Configure ClamAV 0.99.x on OS X 10.10 Yosemite as follws:
4. Configure ClamAV 0.99.x on OS X 10.11 El Capitan and macOS 10.12 Sierra as follws:

Built-in LLVM of ClamAV 0.98.7 and 0.99.x are not compatible with GNU C++ on OS X 10.10 Yosemite and 10.11 El Capitan.
So ClamAV 0.98.7 and 0.99.x built on OS X 10.10 Yosemite or on OS X 10.11 El Capitan have major issues:
- Clamd crashes repeatedly throwing 'Segmentation Fault: 11'
- Clamscan also crashes and fails to scan…
- Freshclam fails to load new database logging:

These problems can be avoided by installing official LLVM.
Versions of LLVM beyond 3.6 seem not to be currently supported in ClamAV, so you should install LLVM 3.6.2.
1. Installing LLVM 3.6.2 Pre-built Binaries
2. To use LLVM installed into /usr/local as a system library instead of the ClamAV's built-in LLVM JIT,
add configuration option as following:
3. Configure ClamAV 0.98.7 on OS X 10.10.x Yosemite as follws:


Apple introduded a new security feature SIP: System Integrity Protection (rootless) to OS X 10.11 El Capitan, so in /usr directory
OS X 10.11 El Capitan has the different file composition from OS X 10.10 Yosemite.
While configuring ClamAV 0.98.7 on OS X 10.11 El Capitan, configuration fails with an error:
1. To solve this configuration issue, install LibreSSL.
Setting search path:
You can confirm the installation:
2. But it's not still sufficient to succeed building.
Building fails with an error:
3. To succeed building ClamAV 0.98.7 on OS X 10.11 El Capitan, set CPPFLAGS:
4. Configure ClamAV 0.98.7 on OS X 10.11 El Capitan as follws:
5. Notes


If you use OpenSSL 1.1.1x to compile ClamAV 0.99.x, add more this configuration.

In last update, Clam AntiVirus developer team introduced JIT compiler to ClamAV® 0.96.
Apple gcc (version: 4.0.1 build: 5370) in Mac OS X 10.4 (aka Tiger) failed to build ClamAV 0.96.x and 0.98.x with JITcompiled in.
With a brief struggle I found a good solution that I will tell you here.
1) First, install LLVM (Low Level Virtual Machine) and LLVM-GCC 4.2 Front End.
2) Second, add this configuration option: --enable-llvm.
Then you can build ClamAV 0.96.x and 0.98.x with JIT compiled in and use new features included in anti-virus toolkit.

Install LLVM (Low Level Virtual Machine) and LLVM-GCC 4.2 Front End
1. Installing LLVM-GCC 4.2 Front End Binaries
2. Setting search path
3. Installing LLVM 2.3

Install MacPorts and the packages
1. Installing MacPorts

2. Installing the packages: bzip2
3. Maintaining MacPorts and installed packages

Compile ClamAV 0.98.x and Install
1. Modify /shared/output.c & output.h to avoid compiling error. (Only needed for compiling ClamAV 0.98.1)
2. ./configure (version 0.98 and 0.98.1)
3. ./configure (version 0.98.3 or later)
4. Make, make check and install ClamAV

To compile ClamAV 0.96.3 or later, bzip2 (Version 1.0.6) that fixes CVE-2010-0405 is required.
Mac OS X has bzip2 (Version 1.0.5) built-inand it is outdated, so you get WARNING as follows while running configuration command.
To solve this problem on Mac OS X 10.4, you can install bzip2 (Version 1.0.6) using MacPorts and add this configuration option:
export LDFLAGS='-L/opt/local/lib' as follows.
Apple has patched the CVE-2010-0405 bug on Mac OS X 10.6.7 but not on Mac OS X 10.4.11.

To compile ClamAV 0.98.3 or later, OpenSSL (Version 0.98y or above including the X509_VERIFY_PARAM function) is required.
Mac OS X 10.4 has OpenSSL 0.9.7l built-in and MacPorts fails to build OpenSSL, so you have to install OpenSSL 0.9.8zh.
1. Install OpenSSL 0.9.8zh
2. Setting search path

Compile ClamAV 0.99.x and Install
To compile ClamAV 0.99.x on Mac OS X 10.4, in addition to installing LLVM Front End, MacPorts, bzip2 and OpenSSL the PCRE library is required as pointed out above.
1. Install PCRE - Perl Compatible Regular Expressions.

2. ./configure
3. Make, make check and install ClamAV

PPC users have to install LLVM-GCC 4.2 Front End Binaries for PPC and configure ClamAV 0.96.x and 0.98.x with different configuration.

Install LLVM (Low Level Virtual Machine) and LLVM-GCC 4.2 Front End
1. Installing LLVM-GCC 4.2 Front End Binaries

Clamxav For Mac Os X 10.13

2. Setting search path
3. Installing LLVM 2.3

Install MacPorts and the packages
1. Installing MacPorts

2. Installing the packages: bzip2
3. Maintaining MacPorts and installed packages

Compile ClamAV 0.98.x and Install
1. Modify /shared/output.c & output.h to avoid compiling error. (Only needed for compiling ClamAV 0.98.x)
2. ./configure
3. Make, make check and install ClamAV

GNU C++ and bzip2 (Version 1.0.6) are installed on Mac OS X and later, so you can simply build ClamAV 0.96.x and 0.98.x with JIT compiled in and use new features included in anti-virus toolkit.

1. On Mac OS X 10.7, after installing Xcode 4.3 in /Applications, you should install the Command Line Tools:

2. Run these commands to make sure that everything is pointed in the right place.

Compile ClamAV 0.98.x and Install
1. ./configure
2. Make, make check and install ClamAV

Compile ClamAV 0.99.x and Install
1. To compile ClamAV 0.99.x, the PCRE library is required as pointed out above.

Clamxav Uninstall Mac Os X

2. ./configure
3. Make, make check and install ClamAV


1. I'm running clamd and freshclam as 'launch daemon' managed by:

2. Edit clamd.conf and freshclam.conf for using ' daemons'.
3. Set appropriate permissions for ClamXav and ClamXav Sentry.
4. Notes




1. When running ClamXav Sentry as 'launch agent', ClamXav Sentry keeps alive.

2. On Yosemite and El Capitan, I'm using this org.clamXavSentry.plist file to avoid ClamXav Sentry's annoying error:
3. Notes


1. Now ClamXav and ClamXav Sentry use combined official and its own virus database as below:
2. To get and update ClamXav Virus Database,

3. When you launch ClamXav 2.8.9.1 and update virus definitions, ClamXav logs follwing error:



1. I'm now running RunFreshclam as 'daemon' instead of freshclam daemon managed by:
/Library/LaunchDaemons/com.clamXav.runfreshclam.plist
2. Edit freshclam.conf for using RunFreshclam ' daemons'.
3. Set appropriate permissions for RunFreshclam (ClamXav version =< 2.8.x).

Clamxav For Mac Os X 10.7

4. Checking and updating virus definitions:



1. ClamXav has a new engine install and uninstall mechanism since version 2.9.

2. Steps to satisfy the requirements for ClamXAV Version 2.19.3 (3715):
1) make empty file called 0.100.1_update_08 inside /usr/local/clamXav/
2) extract gfslogger and RunFreshclam from ClamXAV.app/Contents/Resources/clamavEngineInstaller.pkg
3) place those files into appropriate directory:


5) Set appropriate permissions at /usr/local/clamXav for ClamXAV 2.19.x.

Clamxav For Mac Os X 10.8

3. Now you can run ClamXAV Sentry 3.19.x as 'launch agent' and run RunFreshclam as 'launch daemon' with no issues.

4. Important Notes