客戶現場，安裝sqlserver 2008R2；因為情景需要，客戶指定了一架在用的筆記本在預演。
突然遭遇了從來沒有的問題：
A network error occurred while attempting to read from the file C:..\..\sqlncli.msi 如圖。
因為距離下班時間很近了，很著急也很惱火，搗鼓來搗鼓去，最后打開了控制面板，一看，媽呀好多SQL Server的東東，挨著刪除吧。。。居然就可以安裝了了。。。。
最終發現如果任何 SQLNCLI或者Native Client存在了，就會出現這個問題。
Microsoft大哥居然弄了這么黑的一招。。。
同時看到有人遭遇了類似的悲劇：
Finally got the Client Tools and Mangement Studio installed. What I did was remove Microsoft SQL Server 2008 Native Client in Add or Remove Programs (before I was just trying to uninstall Microsoft SQL Server 2008 and it failed). After Native Client was removed, I reinstalled client tools and mangement studio from a dvd (was mounting the iso before). Everything installed perfectly.
這個人解釋的更多：
The cause of the error
I wondered what was different between my clean test-VM and my server that I was now attempting to install SQL-SERVER 2008 R2 Client Tools and SSMS onto. Both were 64-Bit OS's and same setup, etc., but one was a clean VM. This got me thinking
I had PREVIOUSLY installed JUST the SQLNCLI (SQL-Server Native Client)
for SQL 2008 R2 onto my physical system, in order to test application connectivity to a SQL2008R2 database. So, could that be it!? YES! After uninstalling any previously installed SQLNCLI applications, and re-running the SQL-Server installer, amazingly my "network errors" were gone and the installation was fixed!
Microsoft: GIVE MEANINGFUL ERROR MESSAGES! All the installer had to
do was say that "previous installations of SQLNCLI / native client exist and must be removed before installing"
in fact, the PREREQUISITES-CHECK SHOULD HAVE TESTED FOR THIS
if it can cause a total failure to install!