# \[BUG-13053\] Issue using UDT Nesting **URL:** \ **Category:** Ignition Early Access\ **Created:** [March 7, 2019, 9:57am UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114 "2019-03-07T09:57:58Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![massimo.giacosa](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/massimo.giacosa/32/7489_2.png) [@massimo.giacosa](https://forum.inductiveautomation.com/u/massimo.giacosa)\ **Post date:** [March 7, 2019, 9:57am UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/1 "2019-03-07T09:57:58Z")
Dear all, I am currently using the build **b2019030402**. I created an UDT (in this example called _F\_U\_DEOTrk_) then I inserted it into another UDT (called _F\_U\_DeoStage_). ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/7/72d1c30c01e33bb6f0b66f15e24d28b6f382f756.png) When I try to create a new tag, instance of this second UDT, everything seems to work well (all members are present within the structure): ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/c/c559f986d303301c4e720afb4da50a94a6d5bf5a.png) but, when I apply and save this instance, the tag created does not contain the members present within the original UDT (see _New Instance_ tag in the below image) ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/b/b209d2cc9e44268e034a702c45b1f3ee9330e8a2.png) In the log there is the following message: ![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/e/e47ca507e5201a07e1cfeb121a4aa5a09dd8acab.png) Attached, a copy of the two UDTs: [UdT F\_U\_DeoStage.txt](https://us1.discourse-cdn.com/inductiveautomation/original/2X/a/afbc968aca223d2db6949ad558b5dbe5174e9f00.txt) (218 Bytes) [UdT F\_U\_DEOTrk.txt](https://us1.discourse-cdn.com/inductiveautomation/original/2X/5/53dd4f5b6b15cc1e41837c568bd7e5fffbe2d9d9.txt) (216 Bytes) Let me know for further information. Thank you. Massimo ---
**Author:** ![ggross](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ggross/32/12668_2.png) [@ggross](https://forum.inductiveautomation.com/u/ggross)\ **Post date:** [March 7, 2019, 5:23pm UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/2 "2019-03-07T17:23:37Z")
The error is indicating that the UDT the instance is based on has a circular dependency between itself and one of its members. Can you please post an export of the UDT DataType Definition for **UDT\_DeoBatchTool** and any other UDTs that are included as members? Also, it is easier than I would like to create a new UDT Instance within an existing DataType rather than as an independent tag. It would be a good idea to confirm that the UDT instance was created as its own tag and not within the UDT Definition. Thanks, Garth ---
**Author:** ![massimo.giacosa](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/massimo.giacosa/32/7489_2.png) [@massimo.giacosa](https://forum.inductiveautomation.com/u/massimo.giacosa)\ **Post date:** [March 8, 2019, 8:29am UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/3 "2019-03-08T08:29:02Z")
Hi Garth, I tried to start from the beginning; I created 3 different UDTs: - F\_U\_UDT1: simple UDT that contains only one OPC member - F\_U\_UDT2: UDT that contains 2 OPC members and an instance of F\_U\_UDT1 - F\_U\_UDT3: UDT that contains 2 OPC members and 2 instances of F\_U\_UDT1 (with different names). Then I tried to create tags: - Tag1: instance of F\_U\_UDT1 - Tag2: instance of F\_U\_UDT2 - Tag3: instance of F\_U\_UDT3 The first two tags are correct, the third contains only the name but has no members: ![Image%205](https://us1.discourse-cdn.com/inductiveautomation/original/2X/5/5f7975ecfcbeed11b14e0f52b8d5310b2db2ee46.png) In the log there is the following message: ![Image%206](https://us1.discourse-cdn.com/inductiveautomation/original/2X/1/19a4294bf9514ff08e624b53686d14bd53023e2b.png) Attached, the export of the UDTs and tags: [UDTs.json](https://us1.discourse-cdn.com/inductiveautomation/original/2X/a/a45918bf1f633af304b0bcb0704bbb3ce41a5022.json) (2.3 KB) [tags.json](https://us1.discourse-cdn.com/inductiveautomation/original/2X/3/39fc2b31a2af1a19cbbe9f6c78a555ed93ca8384.json) (850 Bytes) Thanks, Massimo ---
**Author:** ![ggross](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ggross/32/12668_2.png) [@ggross](https://forum.inductiveautomation.com/u/ggross)\ **Post date:** [March 8, 2019, 5:49pm UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/4 "2019-03-08T17:49:27Z")
Appreciate the help in figuring this out. The reason it is failing out is due to an error where a composite UDT containing more than one copy of a different UDT is triggering the circular dependency error (ex. F\_U\_UDT containing 2 members of F\_U\_UDT1). An internal issue has been logged. Garth ---
**Author:** ![joshdunstan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/joshdunstan/32/43306_2.png) [@joshdunstan](https://forum.inductiveautomation.com/u/joshdunstan)\ **Post date:** [March 14, 2019, 4:07am UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/5 "2019-03-14T04:07:14Z")
Hey Garth, any update on this? It’s killing my development! ---
**Author:** ![awalker](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/awalker/32/6874_2.png) [@awalker](https://forum.inductiveautomation.com/u/awalker)\ **Post date:** [March 14, 2019, 3:19pm UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/6 "2019-03-14T15:19:27Z")
This issue was fixed in the build that was uploaded today (3/14). Please let us know if you continue to see this behavior after upgrading. ---
**Author:** ![joshdunstan](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/joshdunstan/32/43306_2.png) [@joshdunstan](https://forum.inductiveautomation.com/u/joshdunstan)\ **Post date:** [March 14, 2019, 9:19pm UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/7 "2019-03-14T21:19:27Z")
Great! Thanks! Confirming its working for me too. ---
**Author:** ![massimo.giacosa](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/massimo.giacosa/32/7489_2.png) [@massimo.giacosa](https://forum.inductiveautomation.com/u/massimo.giacosa)\ **Post date:** [March 15, 2019, 3:30pm UTC](https://forum.inductiveautomation.com/t/bug-13053-issue-using-udt-nesting/23114/8 "2019-03-15T15:30:51Z")
Great, it works. Many thanks. Massimo