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Error Messages Invalid expression or reference: No suitable instance found [seeking]  @(Pega-RULES:DateTime).CurrentDateTime() [candidate functions are]     Rule-Utility-Function    Lib(Pega-RULES:DateTime).CurrentDateTime()
    at com.pega.pegarules.priv.FUAUtil.throwUnresolvedAssemblyError(
    at com.pegarules.generated.model.ra_model_pydefault_e9e0b1fe683abe4cf3b6c6233651b4b6.model_1(
    at com.pegarules.generated.model.ra_model_pydefault_e9e0b1fe683abe4cf3b6c6233651b4b6.perform(
    at com.pega.pegarules.session.internal.mgmt.Executable.applyModel(
    at com.pega.pegarules.session.internal.mgmt.Executable.applyModel(
    at com.pega.pegarules.session.internal.async.AgentRuleUtils.generateDataPage(


Caused by: ** Invalid expression or reference: No suitable instance found [seeking]  @(null:null).PageExists(ClipboardPage,PublicAPI) [candidate functions are]     Rule-Utility-Function    @.PageExists(rulePage,tools)
    at com.pega.pegarules.priv.FUAUtil.activityPreTranIndeterminateConditionalCheck(
    at com.pegarules.generated.activity.ra_action_findruledata_955d88e1545fc08c5302ea4b87dc30ae.step4_circum0(

Steps to Reproduce

Restart the application server.

Root Cause

A defect in Pegasystems’ code or rules.  The system does not guard against attempts to recompile rules which reference Rule-Utility-Functions (RUF) during startup while the Libraries which contain these RUFs are being regenerated.  As a result the referencing Rules fail to compile correctly, resulting in the error.  The error will remain even after the Libraries finish compiling, and even if the Libraries are subsequently recompiled.


Perform the following local-change: Resave the referencing rules.  This will force recompilation of the rules.  As the Libraries are now completed regenerating, the RUF references will be successful.


Published February 27, 2016 - Updated October 8, 2020

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