# Memory Tag Value Changed Event Fires on Startup/Creation with initialChange=True and Uncertain\_InitialValue Previous Value

**URL:** <https://forum.inductiveautomation.com/t/memory-tag-value-changed-event-fires-on-startup-creation-with-initialchange-true-and-uncertain-initialvalue-previous-value/116248>\
**Category:** Ignition\
**Tags:** scripting\
**Created:** [July 2, 2026, 12:50pm UTC](https://forum.inductiveautomation.com/t/memory-tag-value-changed-event-fires-on-startup-creation-with-initialchange-true-and-uncertain-initialvalue-previous-value/116248 "2026-07-02T12:50:57Z")\
**Posts on this page:** 1\
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**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [July 2, 2026, 1:18pm UTC](https://forum.inductiveautomation.com/t/memory-tag-value-changed-event-fires-on-startup-creation-with-initialchange-true-and-uncertain-initialvalue-previous-value/116248/2 "2026-07-02T13:18:28Z")

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1. Yes, to all.

2. The `initialChange` flag means the infrastructure has had a gap in attention (long or short) and **doesn't know** , for sure, what the previous value really is. For memory tags, it is initialized from the value storage, but might be out of date. You are **not** guaranteed that the first "real" value change has `initialChange` false.

3. No. For other than memory tags, `previousValue` is entirely `null` on startup/tag restart. Memory tags try to start up from value storage, if possible. You really should not even touch `previousValue` when `initialChange` is true.

4. None of the above. When `initialChange` is true, **you** must determine from your own recordings, what the previous value was as far as your business logic is concerned. This may require time-consuming DB or historian or API calls that can be avoided when `initialChange` is false.

5. Yes, memory tags have a value storage system, that tries to capture all writes, but obviously cannot guarantee it. If your gateway shuts down or fails over to a redundant backup right after a memory tag write, it may be lost.

If you have business logic that absolutely has to note changes reliably, you need to use a high-availability DB as the source of truth.

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