Wyse Thin client Daylight Saving issue

I had an interesting problem that appeared shortly after the GMT Daylight saving time changed on Sunday evening (31^st March) with Wyse Xenith/Xenith2 thin client devices which are used to access a Citrix VDI environment delivering a Windows 7 Professional desktop to around 800 users.

So what was the issue?

The problem was reported that even though the clock went forward 1 hour the Windows 7 clients where reporting that the time hadn’t changed (gone forward) since the change.  People were not turning up to meeting on time and it caused mayhem.

Taking a look at the time zone set on the Windows 7 client once logged in, I quickly noticed that the TimeZone was set incorrectly (Figure 1)

Figure 1

Normally it would be set to the UK Time Zone (Figure 2)

Figure 2

I tried setting this back and rebooting but once logged in it reverted to the incorrect setting (Figure 1), so were was it getting this from you may ask.

My attention was then focused on to the thin clients to see if anything was set wrong.  After checking I noticed that the time zone was set to “Unspecified” (Figure 3)

Figure 3

I set about testing my theory that it was passing through the Time Zone from the thin client to the Windows 7 desktop.  I amended the correct settings manually (Figure 4) rebooted then logged in to the Windows 7 desktop.

Figure 4

After logging in and checking the time zone was correct (Figure 2) I guess my theory was correct.  So the question is I now need to change this on 800 thin clients so I sat down with a Starbucks and had a think. The easiest way forward was to set this centrally as I didn’t want to visit these thin clients as it would take days.

There are basically a number of ways this can be achieved but this all depends on how your infrastructure is configured.  From past experience with legacy you can centrally hold the config file (xen.ini) which is checked and downloaded to each thin client on startup so this is the method I will be covering.

Basically in the xen.ini file I added a line for the TimeZone (Figure 5) and set it to GMT.

Figure 5

After I rebooted and checked the setting on the thin client (to make sure it was using the central xen.ini file it was set to GMT but set to “Casablanca, Monrovia GMT” which is incorrect (Figure 6).

Figure 6

After checking the available settings on the thin client I found the reason why it was making this setting was because there are two instances of “GMT” in the thin clients’ settings and it was accepting the first GMT instance which unfortunately was wrong.  After trying different permutations I finally got it set the right GMT for the United Kingdom.  You can see the modified TimeZone config below (Figure 7)

Figure 7

Once I checked that the Windows 7 desktop was set correctly (Figure 2) and went about making this new xen.ini file live.  Next time the thin clients were rebooted they would pick up the new settings.

Happy Days 🙂