VirtualBox client CentOS can’t boot up with error message:

1. [FAILED] Failed to start Virtual Machine and Container Registration Service.
2. [FAILED] Failed to start Login Service.
   

Solution

Disable SELINUX config with the following steps during boot up sequence:

1. During Grub boot up stage, press 'e' to edit grub sequence;
2. Add systemd.unit=rescue.target to the end of line with linux16 and boot with rescue mode;
3. Press ctrl+x to continue boot sequence

Config

• CentOS 7 3.10
• VirtualBox 6.0.10

Tricks

• The cause of this boot up issue was difficult to found and the original setting of SELINUX was ‘permissive’ not ‘enabled’. However, this issue may also be owing to bugs in VirtualBox 6.
• During boot up process, by default the boot up is quiet, i.e. no system message will be displayed, only the boot up progress bar is seen. However, pressing Esc key will let you see the detail boot up messages.

The post CentOS VM Client Can’t Boot Up appeared first on LarryLai.

when launching iTunes, it closed immediately after clicking the icon and appeared in half a second, then error screen appeared to ask for “ignore”, “report”, etc.

Solution:

1. Finder -> Applications -> iTunes.app
2. right click -> Get Info
3. Expand “Sharing & Permissions”
4. click bottom right lock icon and input admin password
5. select system permissions
6. click bottom wheel icon and select “Make system the owner”
7. install the latest iTunes pkg

Tricks:

• Without step 6 above, no matter how uninstall, remove iTunes.app and reinstall the latest version, it will fail to restore it properly.
• System always complains when simply removing iTunes.app by stating that iTunes is required by MacOS.
• Even login as root in Terminal command, the directory iTunes.app cannot be removed.
• Asking Apple support through discussions.apple.com, people only suggest reinstall the latest version of iTunes but no one suggest checking wheel icon under Sharing & Permissions of Get Info window.

Config:

• MacOS: High Sierra 10.13.2
• iTunes:  12.7.2.60

The post Cannot launch or remove iTunes from Mac High Sierra appeared first on LarryLai.

After moving mounted volumes from Qnap NAS to iMac as host with CentOS as client, the directory and file ownership cannot be changed to Apache at the client side. No matter using root or user privilege to command the chown.

Solution:

Add the following in iMac’s /etc/exports:

[nfsshare] -rw -maproot=root:wheel

Tricks:

-maproot directive can pass the root control from nfs host to client, without it even changing the directory access and file permission to 777 in host, or changing the mount options at client cannot solve the issue.

Config:

• OSX:        10.12.3
• CentOS:   7.3

The post Cannot Change Ownership on NFS Files appeared first on LarryLai.

Just bought a Wacom Intuos Draw CTL-690, and want to install a note taking app with drawing feature in iMac running OSX Mavericks, found a good one – MS OneNote, but it only support OSX 10.10 or above. Being aware of the possibility that the latest OSX Sierra does not fully support old Adobe CS5.5 Master Collection, I tried to upgrade to OSX Yosemite. After downloaded Yosemite install package on the web as it is unavailable on Apple’s support site any more.

There was error after verifying the system when running the Yosemite installer suggesting contact AppleCare.

Solution:

Directly upgrade to OSX 10.12 Sierra. There is some little problem with Photoshop. Need to install JavaSE again as instructed by Photoshop after upgrade.

Tricks:

• It is good practice to backup the old OS with Time Machine for Mac even though in my case, there is no need to restore to original OS version.
• If upgrading to Sierra has potential application incompatibility issue with new OS, I think there still may be some with Yosemite or El Capitan, why not give Sierra a try as it is 10.12.1 not the xx.xx.0 version.

Config:

• OSX 10.9.5 -> OSX 10.12.1
• Photoshop  12.1

The post Mac OS X Maverick Upgrade appeared first on LarryLai.

OpenSUSE suddenly could not boot to GUI mode, but being kicked out to recovery mode with the CLI mode with the warning of something like no space to write on device, and the hard disk activity light was unexpectedly always on.

Solution:

• At the recovery mode, login as root and delete some snapshots.
• Execute “snapper ls” to get the snapshot numbers
• Execute “snapper delete [start number] – [end number]”
• Reboot

Tricks:

1. This issue probably occurs only on linux system with btrfs partition in which snapshots are automatically generated. Thus, it should be paid extra care to decide whether to use traditional ext3 or ext4 instead of the default partition option: btrfs suggested by OpenSUSE during installation.
2. When typing “df -h”, the storage usage seems to be normal. No storage or any partition full could be noticed.
3. When hard disk activity light always on, it seems that something related to hardware is wrong but actually it doesn’t.
4. My partition config. fully agreed OpenSUSE suggestion that btrfs for / directory and xfs for /home directory. Yesterday, due to some video files transfer from desktop PC to iPhone using FTP, I setup FTP server on desktop using proftpd, the default directory on server side is /srv/ftp. Probably the new video files are so large that btrfs generated large snapshots under / directory.

Config:

• OpenSUSE 13.2
• KDE4 1.0

The post OpenSUSE Boot Up Issue appeared first on LarryLai.

Uploaded keynote file to iCloud through safari, after a day the iPad still could not see it when clicking the “+” sign at top left corner of Keynote in iPad.

Solution:

Go to Settings in iOS device, click iCloud and turn it off for a while then turn it on again

Tricks:

People would ask why not using Google Drive to transfer the files. It is interesting that when you upload a keynote file to Google Drive, the file will become a set of files including data and various image files under a folder with the name of the keynote file, then it is useless to download it to the iOS, i.e. you cannot play anything about the original keynote file in your iOS devices.

Config:

iOS    9.1

The post Demystify iCloud Sync appeared first on LarryLai.

Suddenly found that the Serif fonts appeared in Linux is uglier than those appeared on Mac OS X.

Solution:

Configure Desktop by enabling Use sub-pixel rendering, and choose Slight in Hinting style.

Config:

• OpenSuse 13.1
• KDE 4.11

Tricks:

Some suggestion was to install Microsoft fonts, actually this could be done but still ugly Serif fonts was shown.

The post Ugly Font Appearance in Linux appeared first on LarryLai.

Installed Linux driver for Brother DCP-L2540DW printer driver, then found out that printing for one page or double-sided page is fine, but it always shows error

“ERROR NAME; memoryfull” printed on a page then stop.

when starting to print multiple pages from a file. Not working even tune down the resolution from 600dpi to 300dpi as suggested by Brother’s official support site.

Solution:

Replace driver:

Brother DCP-L2540DW with driver Brother DCP-8045D BR-Script3

by:

Brother DCP-8045D – CUPS+Gutenprint v5.2.9

Tricks:

After installing the rpm package downloaded from Brother’s official support site, there is no driver with name specific for DCP-L2540DW, thus installing 8045D instead.

Config:

• Brother Monochrome Laser Printer DCP-L2540DW
• OpenSUSE 13.1-13.6.1
• CUPS ver. 1.5.4-12.13.1

The post Laser Printer for Linux appeared first on LarryLai.

Suddenly cannot backup using Windows XP built-in backup utility. Error: “Error returned while creating the volume shadow copy: 80042301”.

Solution:

Use suggestion from Adi Oltean as follows:

There are at least two possible causes for this problem:

1. The COM+ Event System service is disabled (open services.msc and, if this is the case, re-enable this service). This service should be enabled by default.
2. The Windows Setup encountered a problem. Just run “REG.EXE QUERY HKLMSystemSetup”. If any of the SystemSetupInProgress/UpgradeInProgress is different than zero, then you will get this message. To fix this issue in this case, please run the following commands:

REG ADD HKLMsystemsetup /v SystemSetupInProgress /t REG_DWORD /d 0/f
REG ADD HKLMsystemsetup /v UpgradeInProgress /t REG_DWORD /d 0 /f

Tricks:

Start -> Run -> Open: services.msc

The post Windows XP Backup Utility appeared first on LarryLai.

OS unbootable and show the following message:

Kernel panic – not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

Solution:

• At waiting to boot loader
• click any key to access the boot kernel menu
• Select previous kernel version other than the default latest installed one

Config:

• CentOS    6.4
• Kernel      2.6.32-431.1.2.0.1.el6.x86_64

Tricks:

Upon upgrading the kernel or installed the kernel-devel packages, the system was still running the current kernel until next system reboot. In case, the reboot schedule was long after this kernel-devel, it is not easy to remember kernel-devel was installed and as a side effect also upgraded the kernel.

The post CentOS Not Bootable after Install Kernel-devel rpm appeared first on LarryLai.